SUPEMLLOYS 2012

SUPEMLLOYS 2012

Proceedings of the

12th International Symposium on Superalloys

Held September 9-13, 2012

at Seven Springs Mountain Resort, Seven Springs, PA

Edited by Eric S. Huron, Roger C. Reed, Mark C. Hardy

Michael J. Mills, Rick E. Montero, Pedro D. Portella, Jack Telesman

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Copyright © 2012 by The Minerals, Metals, & Materials Society. All rights reserved.

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TABLE OF CONTENTS Superalloys 2012:12th International Symposium on Superalloys

Preface xiii Dedication xv Best Paper Award xvii Twelfth International Symposium on Superalloys Committee Members xix

Symposium Keynote Address

Application of Materials and Process Modeling to the Design, Development, and Sustainment of Advanced Turbine Engines 3

W. Gostic

Mechanisms & Models for Mechanical Behavior

Mechanical Behavior and Damage Processes of Udimet 720Li: Influence of Localized Plasticity at Grain Boundaries 15

P. Villechaise, J. Cormier, T. Billot, andJ. Mendez

Deformation Mechanisms Coupled with Phase Field and Crystal Plasticity Modeling in a High-temperature Polycrystalline Ni-based Superalloy 25

H. Deutchman, P. Phillips, N. Zhou, M. Samal, S. Ghosh, Y. Wang, and M. Mills

Controlling the Deformation Mechanism in Disk Superalloy at Low and Intermediate Temperatures 35 Y. Yuan, Y. Gu, Z. Zhong, T. Osada, T. Yokokawa, andH. Harada

Characterization of Strain Accommodation at Grain Boundaries of Nickel-based Superalloys 43 J. Carter, N. Zhou, J. Sosa, P. Shade, A. Pilchak, M. Kuper, Y. Wang, H. Fräser, M. Uchic, andM. Mills

On the Mechanism of Serrated Grain Boundary Formation in Ni-based Superalloys with Low γ' Volume Fraction 53

H. Hong, I. Kim, B. Choi, Y. Yoo, andC. Jo

Fatigue Failure Modes of the Grain Size Transition Zone in a Dual Microstructure Disk 63 T. Gabb, P. Kantzos, B. Palsa, J. Telesman, J. Gay da, and C. Sudbrack

Understanding and Modeling of Grain Boundary Pinning in Inconel 718 73 A. Agnoli, M. Bernacki, R. Loge, J. Franchet, J. Laigo, andN. Bozzolo

Nanoindentation and Nano-compresion Testing of Ni3Al Precipitates 83 B. Gan, H. Murakami, R. Maaß, L. Meza, J. Greer, T. Ohmura, andS. Tin

Local Fracture Toughness and Residual Stress Measurements on NiAl Bond Coats by Micro Cantilever and FIB-based Bar Milling Tests 93

R. Webler, M. Krottenthaler, S. Neumeier, K. Durst, and M. Göken

The Localization of Strain in Low Solvus High Refractory (LSHR) Nickel Superalloy 103 S. Kuhr, G. Viswanathan, J. Tiley, and H. Fräser

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Coupled Analysis of Microstructure Evolution with Creep Deformation in Nickel-based Superalloys by the Phase-field Method I l l

Y. Tsukada, Y. Murata, T. Koyama, N. Miura, and Y. Kondo

New Quantitative Analysis of Contributing Factors to Strength of Disk Superalloys 121 T. Osada, Y. Gu, N. Nagashima, Y. Yuan, T. Yokokawa, andH. Harada

Integration and Automation of Residual Stress and Service Stress Modeling for Superalloy Component Design... 129 G. Shen, N. Cooper, N. Ottow, R. Goetz, andJ. Matlik

Structural Stability of Topologically Close-packed Phases: Understanding Experimental Trends in Terms of the Electronic Structure 135

T. Hammerschmidt, B. Seiser, M. Cak, R. Drautz, andD. Pettifor

The Variability of Fatigue in Notched Bars of IN100 143 A. Rosenberger, D. Buchanan, D. Ward, andS. Jha

Grain Boundary Deformation and Fracture Mechanisms in Dwell Fatigue Crack Growth in Turbine Disk Superalloy ME3 149

J. Dahal, K. Maciejewski, andH. Ghonem

Grain Scale Crystal Plasticity Model with Slip and Microtwinning for a Third Generation Ni-base Disk Alloy 159 J. Song, and D. McDowell

Influence of γ' Precipitate Size and Distribution on LCF Behavior of a PM Disk Superalloy 167 G. Boittin, D. Locq, A. Rafray, P. Caron, P. Kanoute, F. Gallemeau, and G. Cailletaud

Single Crystal Alloys & Behavior

New Single Crystal Superalloys, CMSX®-7 and CMSX®-8 179 J. Wahl, andK. Harris

Development of an Oxidation-resistant High-strength Sixth-generation Single-crystal Superalloy TMS-238 189 K. Kawagishi, A. Yeh, T. Yokokawa, T. Kobayashi, Y. Koizumi, and H. Harada

A New Single Crystal Superalloy for Power Generation Applications 197 R. Reed, J. Mover are, A. Sato, F. Karlsson, and M. Hasselqvist

Influence of Ruthenium on Topologically Close Packed Phase Precipitation in Single-crystal Ni-based Superalloys: Numerical Experiments and Validation 205

R. Rettig, and R. Singer

Deformation and Damage Mechanisms during Thermomechanical Fatigue of a Single-crystal Superalloy in the <001> and <011> Directions 215

M. Segersäll, J. Mover are, K. Simonsson, and S. Johansson

The Effect of Crystal Orientation and Temperature on Fatigue Crack Growth of Ni-based Single Crystal Superalloy 225

H. Kagawa, and Y. Mukai

Comparison of the Mechanical Behavior and Evaluation of Different Damage Mechanisms in an Equiaxed and a Single Crystal Superalloys Subjected to Creep LCF and TMF 235

E. Vacchieri, and A. Costa

Microstructural Evolution of Single Crystal and Directionally Solidified Rejuvenated Nickel Superalloys 245 A. Rowe, J. Wells, G. West, and R. Thomson

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Development of Ni Based DS Superalloy with Excellent Oxidation Resistance and LCF Properties for Power-generation Gas Turbines 255

A. Yoshinari, O. Tamura, Y. Murata, andM. Morinaga

Effect of the Prior Microstructure Degradation on the High Temperature/Low Stress Non-isothermal Creep Behavior of CMSX-4® Ni-based Single Crystal Superalloy 265

R. Giraud, J. Cormier, Z. Hervier, D. Bertheau, K. Harris, J. Wahl, X. Mühet, J. Mendez, and A. Organista

A Proposal on Quantitative Treatment of Multiple Cracks Nucleating in Single Crystal Superalloys 275 Y. Mukai, andH. Kagawa

Quantitative Analysis of Creep Strengthening Factors in Ni-base Single Crystal Superalloys 285 T. Yokokawa, H. Harada, K. Kawagishi, Y. Koizumi, and T. Kobayashi

Low Cycle Fatigue of CMSX-4 in Off-axis Orientations and the Effect of a Multi-axial Stress State 293 N. Barnard, D. MacLachlan, N. Jones, J. Mason-Flucke, S. Bagnall, andM. Bache

Effects of Y and La Additions on the Processing and Properties of a Second Generation Single Crystal Nickel-base Superalloy CMSX-4 301

H. Pang, I. Edmonds, C. Jones, H. Stone, and C. Rae

Influence of Crystallographic Orientation on Creep Behavior of Aluminized Ni-base Single Crystal Superalloys 311

F. Latief, K Kakehi, H. Murakami, and K Kasai

Prediction of Initial Oxidation Behavior of Ni-base Single Crystal Superalloys: A New Oxidation Map and Regression Analysis 321

A. Suzuki, K. Kawagishi, T. Yokokawa, T. Kobayashi, andH. Harada

Modeling of the Influence of Oxidation on Thin-walled Specimens of Single Crystal Superalloys 331 M. Bensch, A. Sato, N. Warnken, E. Affeldt, R. Reed, and U. Glatzel

Rejuvenation of Ni-based Superalloys GTD444(DS) and Rene N5(SX) 341 L. Rettberg, M. Tsunekane, and T. Pollock

Creep and Fatigue

Stress Rupture and Fatigue in Thin Wall Single Crystal Superalloys with Cooling Holes 353 E. Sun, T. Heffernan, and R. Helmink

Evolution of Grain Boundary Precipitates in a Directionally Solidified Ni-base Superalloy during High Temperature Creep 363

D. Wang, C. Liu, J. Zhang, andL. Lou

Thermomechanical Fatigue of Single-crystal Superalloys - Influence of Composition and Microstructure 369 J. Mover are, M. Segersäll, A. Sato, S. Johansson, andR. Reed

Processing to Fatigue Properties: Benefits of High Gradient Casting for Single Crystal Airfoils 379 C. Brundidge, and T. Pollock

Secondary Creep of Thin-walled Specimens Affected by Oxidation 387 M. Bensch, E. Fleischmann, C. Konrad, M. Fried, C. Rae, and U. Glatzel

Sustained Macroscopic Deflected Fatigue Crack Growth in Nickel Based Superalloy 720Li 395 C. Schoettle, P. Reed, M. Star ink, I. Sinclair, D. Child, G. West, andR. Thomson

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Analysis of Deformation Substructures in a Notched LCF Sample under Dwell Condition in a Ni-based Superalloy 403

G. B. Wiswanathan, K. Bain, D. Huber, S. Jha, S. Sam, J. Tiley, C. Woodward, andH.L. Fräser

Effect of Thermal Cycling on High Temperature Creep of Coated CMSX-4 411 R. Goti, B. Viguier, andF. Crabos

Relative Contributions of Secondary and Tertiary γ' Precipitates to Intergranular Crack Growth Resistance in IN 100 Alloy 421

K. Maciejewski, andH. Ghonem

Fatigue Crack Propagation in Thin-wall Superalioys Component; Experimental Investigation via Miniature CT Specimen 431

M. Sakaguchi, T. Tsuru, andM. Okazaki

An Analysis of Fatigue Crack Initiation using 2D Orientation Mapping and Full-field Simulation of Elastic Stress Response 439

C. Stein, S. Lee, and A. Rollett

Specific Failures of Superalioys with Thermal Barrier Coatings Subjected to Thermo-mechanical Fatigue Loadings with a Thermal Gradient in a Simulated Combustion Environment 445

M. Okazaki, S. Yamagishi, M. Sakaguchi, andS. Rajivgandhi

Effects of Alloying Elements on Elastic, Stacking Fault and Diffusion Properties of Fee Ni from First-principles: Implications for Tailoring the Creep Rate of Ni-base Superalioys 455

C. Zacherl, S. Shang, D. Kim, Y. Wang, andZ. Liu

The Effect of Carbide Decomposition and Reformation on Rupture Lives of IN738LC during Multiple Reheat Treatment and Degradation Cycles 463

S. Pahlavanyali, M. Wood, andG. Merchant

A New Approach to Modeling of Creep in Superalioys 473 R. Oruganti, M. Karadge, S. Nalawade, S. Kelakanjeri, andF. Mastromatteo

Physics-based Modeling of Thermo-mechanical Fatigue in PWA 1484 481 R. Amaro, S. Antolovich, R. Neu, and A. Staroselsky

Rafting during High Temperature Deformation in a Single Crystal Superalloy: Experiments and Modeling 491 B. Fedelich, A. Epishin, T. Link, H. Klingelhoff er, G. Kunecke, and P. Portella

Cyclic Dwell Fatigue Behavior of Single Crystal Ni-base Superalioys With/Without Rhenium 501 S. Yandt, X. Wu, N. Tsuno, and A. Sato

Models for Processing & Properties

Direct Laser Fabrication of INCONEL-718: Effects on Distortion and Microstructure 511 L. Parimi, M. Attallah, J. Gebelin, and R. Reed

Effect of Off-stoichiometry and Ternary Additions on Planar Fault Energies in Ni3Al 521 K. Vamsi, andS. Karthikeyan

Interfaces in Ni-based Superalioys and Implications for Mechanical Behavior and Environmental Embrittlement: A First-principles Study 531

S. Sanyal, U. Waghmare, T. Hanlon, E. Hall, P. Subramanian, and M. Gigliotti

Molecular-Dynamics Simulations of Molten Ni-based Superalioys 537 C. Woodward, J. Lill, M. Asta, andD. Trinkle

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Prediction of Plastic Strain for Recrystallization during Investment Casting of Single Crystal Superalloys 547 C. Panwisawas, H. Mathur, J. Gebelin, D. Putman, P. Withey, N. Warnken, C. Rae, and R. Reed

Progress of Research on P/M and Spray-formed Superalloy in ISCPM, USTB 557 C. Ge, Y. Zhang, Y Xu, W. Shen, Y. Zhang, andH. Wu

Weld Solidification Behavior of Ni-base Superalloys for Use in Advanced Supercritical Coal-fired Power Plants 563

D. Tung, andJ. Lippold

Sputtered Ni-base Superalloys for Microscale Devices 569 D. Burns, Y. Zhang, T. Weihs, andK. Hemker

Laser Powder Bed Fabrication of Nickel-base Superalloys: Influence of Parameters; Characterisation, Quantification and Mitigation of Cracking 577

L. Carter, M. Attallah, and R. Reed

On Liquation and Liquid Phase Oxidation during Linear Friction Welding of Nickel-base IN 738 and CMSX 486 Superalloys 587

M. Amegadzie, O. Ola, O. Ojo, P. Wanjara, andM. Chaturvedi

Microstructure Development during Controlled Directional Solidification in Alloy 718 595 A. Patel, J. Erbrick, K. Heck, andG. Maurer

Numerical Simulation of Microstructure Formation during Solidification and Heat Treatments of Ni Base Superalloys 601

L. Rougier, A. Jacot, C. Gandin, P. Di Napoli, P. Thery, and V. Jaquet

Effects of Hammer Peening and Aging Treatment on Microstructure, Mechanical Properties and Corrosion Resistance of Oil-grade Alloy 718 609

T. Chen, H. John, J. Xu, J. Hawk, andX. Liu

Dendrite Bending during Directional Solidification 615 J. Aveson, G. Reinhart, H Nguyen-Thi, N. Mangelinck-Noel, A. Tandjaoui, B. Billia, K. Goodwin, T. Lafford, J. Baruchel, H. Stone, andN. D'Souza

A Closed Concept to Associate the Hot-forging Process Controlled Microstructure with Fatigue Life 625 M. Stoschka, M. Stockinger, H Maderbacher, and M. Riedler

Polycrystalline γ(Νί)/γ'(Νϊ3Α1) - 5(Ni3Nb) Eutectic Ni-base Superalloys: Chemistry, Solidification and Microstructure 633

M. Xie, R. Helmink, andS. Tin

Two Integrated Experimental and Modeling Approaches to Study Strain Distributions in Nickel and Nickel-base Superalloy Polycrystals 643

T. Turner, P. Shade, J. Schuren, M. Groeber, M. Miller, andM. Uchic

Development and Application of an Optimization Protocol for Directional Solidification: Integrating Fundamental Theory, Experimentation and Modeling Tools 653

J. Miller, and T Pollock

INCONEL718 Single and Multipass Modelling of Hot Forging 663 J. de Jaeger, D. Solas, T. Baudin, O. Fandeur, J. Schmitt, and C. Rey

Computational Fluid Dynamics Modelling of Heat Treatment of Single Crystal Nickel Based Superalloys for Turbine Blade Application 673

F. Cosentino, N. Warnken, J. Gebelin, R. Broomfield, and R. Reed

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Alloy & Coating Development Alloying Effects in the γ' Phase of Co-based Superalloys 685

A. Mottura, A. Janotti, and T. Pollock

Creep Strength and Microstructure of Polycrystalline γ' - Strengthened Cobalt-base Superalloys 695 A. Bauer, S. Neumeier, F. Pyczak, andM. Goken

Quaternary Alloying Effects and the Prospects for a New Generation of Co-base Superalloys 705 H. Yan, V. Vorontsov, J. Coakley, N. Jones, H. Stone, andD. Dye

Dynamic Strain Aging in Ni Base Alloys with Different Stacking Fault Energy 715 C. Cui, C. Tian, Y. Zhou, T. Jin, andX. Sun

The Effect of Water Vapor and Superalloy Composition on Thermal Barrier Coating Lifetime 723 B. Pint, J. Haynes, K. Unocic, and Y. Zhang

Potential of the Halogen Effect for the Formation of a Protective Alumina Scale on Ni-base Superalloys 733 H. Zschau, andM. Schütze

Environmental and Dwell Effects on the Damage Tolerance Properties of ATI 718Plus® Alloy 741 R. Kearsey, J. Tsang, S. Oppenheimer, andE. McDevitt

Microstructural Characterisation of High Temperature Oxidation of Nickel Base Superalloy RRIOOO and the Effect of Shot-peening 751

S. Cruchley, M. Taylor, H. Evans, P. Bowen, M. Hardy, andS. Stekovic

Experimental Determination of TTT Diagram for Alloy 718Plus® 759 D. Srinivasan, L. Lawless, andE. Ott

Development of a New 760°C (1400°F) Capable Low Thermal Expansion Alloy 769 M. Fahrmann, K. Srivastava, andL. Pike

Low Cycle Fatigue Behavior of a New Wrought Ni-Co-base Disk Superalloy TMW-4M3 779 Z. Zhong, Y. Gu, Y. Yuan, T. Osada, T. Yokokawa, andH. Harada

On the Development of Cast ATI 718Plus® Alloy for Structural Gas Turbine Engine Components 787 B. Peterson, D. Frias, D. Brayshaw, R. Helmink, S. Oppenheimer, E. Ott, R. Benn, andM. Uchic

Characterization and Modelling of Ni Based Superalloy Materials with a Dual Layered MCrALY Coating System 795

Y. Liu, M. Karunaratne, M. Jepson, and R. Thomson

The Development and Validation of a New Thermodynamic Database for Ni-based Alloys 803 J. Bratberg, H Mao, L. Kjellqvist, A. Engström, P. Mason, and Q. Chen

Alloying Effects on Heat-treated Microstructure in Co-Al-W-base Superalloys at 1300°C and 900°C 813 F. Xue, M. Wang, and Q. Feng

High Temperature Creep of New L12 Containing Cobalt-base Superalloys 823 M. Titus, A. Suzuki, and T. Pollock

Polycrystalline γ-γ'-δ Ternary Eutectic Ni-base Superalloys 833 S. Tin, A. Rodriguez, A. DiScuillo-Jones, R. Helmink, and M. Hardy

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Models and Behavior of Disk Alloys Dwell Notch Low-cycle Fatigue Performance of Powder Metal Alloy 10 845

D. Greving, P. Kantzos, J. Neumann, D. Rice, andH. Kington

Dwell Notch Low Cycle Fatigue Behavior of a Powder Metallurgy Nickel Disk Alloy 853 J. Telesman, T. Gabb, Y. Yamada, L. Ghosn, D. Hornbach, andN. Jayaraman

Oxidation and the Effects of High Temperature Exposures on Notched Fatigue Life of an Advanced Powder Metallurgy Disk Superalloy 863

C. Sudbrack, S. Draper, T. Gorman, J. Telesman, T. Gabb, andD. Hull

Grain Boundary Engineering Alloy 706 for Improved High Temperature Performance 873 A. Detor, A. Deal, and T. Hanlon

Residual Stress Evolution during Manufacture of Aerospace Forgings 881 J. Rolph, M. Preuss, N. Iqbal, M. Hofmann, S. Nikov, M. Hardy, M. Glavicic, R. Ramanathan, and A. Evans

Characterization and Computational Modeling of Minor Precipitate Phases in Alloy LSHR 893 H. Jou, G. Olson, T. Gabb, A. Garg, andD. Miller

An Advanced Cast-and-Wrought Superalloy (TMW-4M3) for Turbine Disk Applications Beyond 700°C 903 Y. Gu, Z. Zhong, Y. Yuan, T. Osada, C. Cui, T. Yokokawa, andH. Harada

AD730TM - A New Nickel-based Superalloy for High Temperature Engine Rotative Parts 911 A. Devaux, B. Picque, M. Gervais, E. Georges, T. Poulain, and P. Heritier

Author Index 921

Subject Index 925

Alloys Index 929

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Preface The purpose of the International Symposium for Superalloys, which takes place only every four years, is to provide a forum for researchers, producers, and users to exchange recent technical information on these high temperature, high performance materials used in gas turbine engines and related products. The overriding goal of the symposium is to highlight new initiatives and future growth opportunities for superalloys, recent advances in the understanding of the behavior of these materials, and progress in integrating these materials into new systems. The first symposium, held over forty years ago, emphasized phase instabilities in superalloys. Since then, the scope of the symposium has expanded markedly to cover all aspects of research, development, production and application of these materials. Over the years, this Symposium has developed rich traditions, encompassing a high quality publication available before the conference, vigorous technical presentation and discussion at the conference, and enduring memories after the conference, facilitated by the Seven Springs Resort venue.

This, the Twelfth Symposium, takes place at a time when there is an increased momentum in a key new area - the use of modeling and simulation in materials optimization, processing, and design application. Trends in the superalloys industry are requiring improvements in alloy capability requiring compositions and processing to be optimized within narrowing constraints for processing, properties, and cost. All of this must be accomplished with reduced cycle time and development cost. Modeling and simulation is critical to this area - by improving the fidelity of development efforts, by enabling reduction in testing and development iteration, and by allowing increased speed in development and implementation. While significant advances in the fundamental understanding and sophistication of materials models have been made, the major challenge for the superalloy community is to apply these models across the life cycle of superalloys, from alloy and process design, then to industrial processes in the factory, and finally to materials used in production. Therefore, the Superalloys 2012 symposium seeks to highlight advances made possible by practical application of modeling and simulation. The Superalloys 2012 symposium includes papers in its traditional focus areas of alloy development, processing, mechanical behavior, and coatings and environmental effects, but with an increased focus on how modeling tools were developed and applied in these areas. With this emphasis, the Symposium intends to further strengthen the links between the academic, supply chain, and product-user members of the superalloy community.

The keynote topic of this symposium is well aligned with the theme. The keynote topic - provided by William Gostic of Pratt and Whitney - highlights how advances in materials modeling have been used at Pratt & Whitney in the development of their advanced engines.

Starting with the Second Symposium in 1972, each symposium and its corresponding published proceedings have been dedicated to an individual as a means of honoring his or her contributions to the superalloy industry. The Twelfth International Symposium is dedicated to Dr. Anthony Giamei, a true pioneer of our field. Further information concerning Dr. Giamei's career and contributions will be found on the following pages.

Finally, it should be noted this symposium would not have been possible without the efforts of the current and past members of the International Symposium on Superalloys committees. The Program Committee for the Twelfth Symposium, listed below, was responsible for preparation of the technical program, including critical review of abstracts and manuscripts for originality, technical content and pertinence to industry. The entire Organizing Committee, listed elsewhere in this book, devoted considerable effort to organizing all other aspects of the symposium.

We would like to also recognize the tremendous work of the TMS staff, particularly Louise Wallach, Trudi Dunlap, Lisa Breese, Margie Castello, Bob Demmler, and Christina Raabe Eck, in helping to organize a successful conference.

Eric S. Huron Roger C. Reed Mark C. Hardy Michael J. Mills Rick E. Montero Pedro D. Portella Jack Telesman

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Dedication

Dr. Anthony Giamei

The 12th International Symposium for Superalloys is dedicated to Dr. Anthony Giamei, for his substantial and pioneering contributions to our field, in particular related to

directional solidification of single crystal turbine blade alloys.

The Superalloys 2012 Symposium is dedicated to Dr. Anthony F. Giamei. Dr. Giamei's career extended over 35 years. Given the theme of this year's symposium, which seeks to highlight advances in superalloys made possible by practical application of modeling and simulation, Dr. Giamei is a most appropriate honoree. Dr Giamei's technical career started with seminal experiments in casting technology which led to the successful development of practical processing techniques for growth of single crystal turbine blades. He was a pioneer in the development and use of computer modeling for casting applications which ultimately led to him assuming the leadership of the P&W computational process modeling group.

Dr. Anthony F. Giamei was born in Coming, NY in October 1940. He attended Yale University during the period 1958 to 1962, graduating cum laude with a BE in Metallurgy. He pursued graduate studies at Northwestern University, earning a PhD in Materials Science in 1966. Upon graduating, he took a position at Pratt & Whitney Aircraft where he worked for 14 years (until 1980), holding various positions in the Advanced Materials Research and Development Laboratory and later the Materials Engineering and Research Laboratory. From 1981 to 1999, Dr. Giamei worked at the United Technologies Research Center where in the latter part of his career he headed the Computational Materials Science activity, leading work in the areas of modeling, strengthening, joining and solidification of both Ni-based and titanium alloys.

At Pratt & Whitney in 1966, Dr Giamei began his professional career in the group headed by Frank VerSnyder, who published his seminal US patent (No 3,260,505 'Gas Turbine Element') concerning directional solidification (DS) casting that same year. Subsequently, Dr. Giamei and VerSnyder's group were able to refine these ideas so that the grain boundaries could be removed entirely from turbine blade airfoils. From this work flowed the development and application of the mass-produced single-crystal airfoils used in the modern gas turbine engine; Dr Giamei was directly responsible for practical aspects of the single crystal casting process - including seeding, helical grain selectors and ceramic moulds - needed to ensure that this

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technology came to fruition. When it became apparent that some of the new alloys were prone to melt-related defects such as freckles, Dr. Giamei carried out seminal work to deduce the mechanism for freckling, and published several important papers on this topic (see for example "On The Nature of Freckles in Nickel-Base Superalloys", Metall. Trans. 1, 1970, p. 2185). Other work was concerned with alloy design: phase identification, phase stability/equilibria, strengthening mechanisms, processability and the inter-relationship between these topics. His work in these areas culminated in the optimization of the composition of alloys such as PWA1484 which is still used widely today. Later, Dr. Giamei was one of the first to embrace computer modeling methods for the numerical analysis of heat flow in castings, and championed their use of both within Pratt & Whitney and throughout the high temperature materials community.

In thirty-five years of professional activities, Dr. Giamei made pioneering contributions to the field of high temperature alloys and directional solidification processing. His interests have been extraordinarily broad, including monocrystal growth, single crystal creep anisotropy, characterization both of superalloys and eutectic systems, heat transfer, computer-based modeling, processing and process control, joining, electron beam melting, directional recrystallization and high temperature mechanical properties. He has published widely, both in journals, books and conference proceedings (80 articles) and the patent literature (25 as author or co-author). Dr. Giamei won the UTC George Mead Medal for Engineering Achievement in 1981, was elected a fellow of the American Society of Metals in 1977 and has served on the board of TMS.

Past Dedicatees

1972 - Clarence Bieber

1976 - Falih Damara

1980-Rudy Thielman

1984-Günther Mohling

1988-Herb Eiselstein

1992-Carl Lund

1996-John Radavich

2000 - Wilfred "Red" Couts

2004 - Fred Pettit

2008 - Raymond Decker

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Best Paper Award The following paper was selected by the Awards Committee of the International Symposium on Superalloys as winner of the

Best Paper Award for the Twelfth Symposium. The selection was based on the following criteria: originality, technical content, pertinence to the superalloy and gas turbine industries and clarity and style:

Influence Of γ Precipitate Size And Distribution On LCF Behavior Of A PM Disk Superalloy

G. Boittin, D. Locq, A. Rafray, P. Caron, P. Kanoute, F. Gallerneau and G. Cailletaud

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Twelfth International Symposium on Superalloys Committee Members

General Chair: Roger Reed, University of Birmingham

Secretary: Sammy Tin, Illinois Institute of Technology

Treasurer: Gern Maurer, ASM International

Program Chair: Eric Huron, GE Aviation

Program Committee: Roger Reed, University of Birmingham Mark Hardy, Rolls-Royce pic

Mike Mills, The Ohio State University Rick Montero, Pratt & Whitney

Pedro Portella, BAM Jack Telesman, NASA Glenn Research Center

Publications Chair: Rick Montero, Pratt & Whitney

Arrangements Chair: David Novotnak, Carpenter Technology Corp.

U.S. Publicity: Jacqueline Wahl, Cannon-Muskegon Corp.

International Publicity/Student Relations: Cathie Rae, University of Cambridge

Asian Publicity: Akihiro Sato, IHI Corporation

Awards Chair: Ken Green, Rolls-Royce Corporation

Awards Committee: Tresa Pollock, University of California-Santa Barbara Bob Stusrud, Rolls-Royce Corporation

Bob Kissinger, GE Aviation

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Symposium Keynote Address

Superalloys 2012: 12"1 International Symposium on Superailoys Edited by: Eric S. Huron, Roger C. Reed, Mark C. Hardy, Michael J, Mills, Rick E. Montero, Pedro D. Portella, Jack Telesman

TMS (The Minerals, Metals & Materials Society), 2012

APPLICATION OF MATERIALS AND PROCESS MODELING TO THE DESIGN, DEVELOPMENT AND SUSTAINMENT OF ADVANCED TURBINE ENGINES

William Gostic

Pratt & Whitney, 400 Main Street, East Hartford, CT 06108, USA

Keywords: Integrated Computational Materials Engineering (ICME), Process Modeling, Turbine Engine, Turbine Components, F135 Engine, Geared Turbo Fan™ Engine

Abstract Introduction

Turbine engines provide a challenging environment for materials. The temperature, environment, stress and the time durations over which components are exposed are tremendous. Turbine engines, like other energy and power generation systems, are being ever pushed to increase performance and fuel efficiency. The continued drive is requiring both engine architecture and associated materials changes to meet the need for increase capability. Materials are being asked to provide increased temperature capabilities to support enhanced engine cycles, while at the same time are being required to be lighter weight for increased operational speeds or engine performance. Likewise advances in materials and or materials processing may enable components with reduced engine part count, each designed to more efficiently convert fuel into thrust. These challenges are requiring new materials, and new and novel approaches to apply existing materials.

An approach being taken to meet these challenges is through further integration of materials, processes and design functions. Integration of material and manufacturing process design efforts seamlessly with component design processes requires new tools and methods. Integrated computational materials engineering (ICME) is providing the path to holistic linking of material, process and component design optimization. Materials models are providing enhanced materials design definitions by enabling greater physics-based understanding of the fundamental behavior of materials. Compilations of materials and process models effectively ''map the genome" of materials and greatly expand the ability for component designer to fully utilize the capabilities of engineered materials, whether emerging new materials or existing materials. This approach to integrated materials, process and design engineering will be the path to enable major changes in future advanced turbine systems. These tools and methods have already made significant impact on current and emerging engine systems.

Turbine engines are continuing to evolve to support increased customer requirements for performance and efficiency. The advancement in engine system capabilities is closely linked to changes in system architecture, component designs and materials requirements. Materials continue to play a major role in the capabilities for turbine engines and often enable significant improvements in operational performance and or durability as evidenced by the F135 engine for the F-35 Joint Strike Fighter or the Geared Turbo Fan (GTF)™ for the Airbus A320 NEO.

The challenge we have today is to more rapidly enable change in system and component design with new materials or more complete use of existing materials. This challenge can be readily seen through the legacy means of defining a materials capability in the traditional forms of materials specifications, design allowable, and specific print or manufacturing process control requirements. Evolution of how we define materials may be the path toward the ability to further exploit the full capabilities of materials. Materials and process modeling is helping to provide a new means of defining materials and are being applied at an ever increasing rate to design activities and associated materials and process optimization efforts.

Traditional development approaches for newer, more advanced turbine engines often required development of new, more advanced materials. Development of new materials is both costly and time consuming, and has been primarily conducted through empirical trial and error methods and often out of time sync with new systems designs. Substantial physical manufacturing and testing of materials has been required to establish a mechanical property capability definition for a material based on the analysis of a compilation of test data from a range of component configurations and processing conditions. Traditional materials definitions for design system application resulted in materials design curves that represent a statistically derived lower limit on each critical material

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property. The material samples tested and included in the design database were developed based on a material specification, which described to a given tolerance, the chemistry, product form and potentially limited processing window requirements. The data that were generated based upon the materials specification were considered to be of the same pedigree and would all be included in the single population analyzed for the design curve minimum property values. As is known to the materials community, the wide scatter in observed materials properties are a result of specific and often known causes, such as local strain, cooling rate, texture, etc., which are not often taken into account in the analysis of the specific single material population for the material definitions.

As modeling and simulation tools have become available throughout industry and to the design community, further refinement of materials definitions has occurred. Component location-specific properties can now be defined through fine-scale gradients in properties or by more simplistic zoning of volumes within components which are defined by different materials requirements and capabilities. Materials and process modeling tools provide for enhanced understanding of the physics which drive the evolution of materials properties on a location-specific basis and enable this ability to more discreetly define final mechanical properties on a local basis within components.

Materials and process models are becoming closely linked to various stages of the design process. Conceptual design processes provide needed input to the materials community regarding future requirements for materials. These requirements are no longer vague, but rather are in the form of detailed component requirements spatially distributed about notional components. Designers and materials engineers can utilize materials and process models to define a notional requirement for the material that will fulfill the future requirements. This upfront interactive approach effectively enables materials engineers to develop a virtual material with chemistry, microstructure and processing requirements that produce a virtual set of mechanical property capabilities that can then be applied to the design and analysis of conceptual components. If the virtual material capabilities meet the needs for the future requirements, focused material development can then be initiated with a very focused scope and well defined set of materials parameters to achieve the desired capabilities. This was the goal of the DARPA Accelerated Insertion of Materials (AIM) program, and which was successfully demonstrated. [1]

Preliminary design functions occur to establish the bounds on the overall engine architecture and sub-system requirements based on overall system performance targets, including fuel efficiency, thrust, weight and cost. This point in the design process is critical for materials

interactions. Enhanced materials definitions, which include the synergy between the inherent material capability and the strong influence of component configuration and manufacturing methods on the component location-specific properties, are needed to enable large potential architecture changes. Changes in the overall engine cycle and or architecture can only effectively be accomplished early in the preliminary design process. If a material can enable architecture change, this often results in huge overall system improvements in efficiency, performance and/or cost.

Figure 1 shows a cross-sectional schematic of the F135 military turbine engine. This unique architecture along with the materials and associated manufacturing processes result in an engine capable of supersonic operation as well as powered lift short take off and vertical landing (STOVL) operation.

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Figure 1. Schematic showing a cross-sectional view of the F135 military turbine engine.

Figure 2 shows a schematic of an advanced commercial geared turbo fan engine, where the fan stage and low pressure turbine module are no longer directly coupled. This enables operating each section of the turbine engine within its optimal efficiency range via light weight, durable engine architectures. The ability to decouple specific engine modules eliminates the constraint one module has on another regarding engine operating conditions thereby enabling significant improvements in fuel efficiency and noise characteristics. With the fan decoupled from the low pressure compressor (LPC) and low pressure turbine (LPT), the LPC and LPT can operate at higher speeds, resulting in improved efficiency. Whereas the fan can be operated at lower speeds utilizing non-conventional materials and fabrications methods. The result is a lighter weight fan with improved propulsive efficiency generating a significantly lower noise signature. This new operating capability now allows materials to be utilized to their fullest for each specific module.

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Figure 2. A cross-sectional view of the Geared Turbo Fan™ engine.

Detailed design processes are also important for materials and process selection and deployment. As architectures change, the influence of subtle materials changes can be enormous. New engine architectures are now more effective in taking advantage of new lighter weight and higher temperature materials. Examples of various aspects of conceptual, preliminary and detailed design efforts related to materials and process development and selection will be further covered throughout the remainder of this paper along with how materials and process modeling has been influencing and enabling many of these efforts.

Application of Materials and Manufacturing Process Modeling and Simulation Tools

Materials and process modeling tools have been developed and deployed for specific applications for several decades. The forging industry for example uses deformation simulation to ensure lowest possible materials utilization, but at the same time eliminating risks of forging related material defect formation. Modeling of forging processes was used extensively in the development of the GTF and F135 fan, compressor and turbine so as to optimize material properties as well as to improve the buy to fly ratio of the forgings.

Figure 3 is an example of a typical forging process simulation of a fan blade utilized to optimize production manufacturing processes to ensure final component requirements are achieved. Based on the simulation efforts, optimized input material and intermediate manufacturing configurations were established. Criteria for forging strain locally and globally have been developed to guide the assessment and optimization process.

Figure 3. Outputs of process models that detail predicted effective strain following two separate forgings steps for a fan blade. Deformation process simulation is used to ensure optimized strain level, strain rate, and temperatures are achieved during each step of the forging process. (Source: D. Selfridge, Alcoa Forgings, Cleveland, OH)

The casting industry has employed solidification models to predict and optimize the processing parameters for advanced turbine engine airfoils. In addition to prediction and subsequent elimination of casting defects, such as porosity, hot tear, freckles and recrystallized grain structure, the control of single crystal orientation is critical for optimum material and component capabilities. A range of physics-based casting and microstructure evolution models have been developed and deployed to production design optimization. Prediction and control of casting microstructure and elimination of casting defects supports enhanced capabilities for sustained service applications as well as for cyclic missions where thermo-mechanical fatigue (TMF) can significantly affect overall component life. Figure 4 shows an example of a typical casting simulation output. This simulation enabled the casting supplier to modify the gating scheme for a mold cluster of commercial engine low pressure turbine blades to avoid a potential hot spot and associated shrinkage porosity.

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Figure 4. A ProCast™ simulation for several commercial engine low pressure turbine blades (LPT) showing a potential area of risk for shrinkage porosity at the transition between the blade shroud and airfoil. ProCAST is a trade mark name of the ESI Group.

Modeling of the turbine airfoil castings was used in the development of the F135 engine. Modeling in conjunction with next generation turbine cooling schemes resulted in the F135 engine incorporating the highest turbine inlet temperatures ever achieved in an operational gas turbine engine. Furthermore, casting modeling was used in the development of the specially oriented single crystal turbine blades that enabled improved structural capability and performance of the F135 Low Pressure Turbine. Control of the primary and secondary orientations and tolerances was enabled through model-assisted process design.

Materials and process models are also being applied to other materials, manufacturing and service processes, such as coating application, oxidation and corrosion behavior. Prediction of material pedigree throughout the manufacturing process is important, but the continued evolution of microstructure and mechanical properties during service provide valuable information for life prediction, repair and overhaul requirements. The PROGNOSIS program demonstrated a number of applications where component microstructure (constituent phases and metallurgical damage) can be predicted and applied to component life requirements based on operation and accumulation of mission unique cycles. [2]

It is clear that predictive tools are becoming a necessity for defining and optimizing materials and processes for future engine components. ICME, or the complete holistic application of materials and process models, is providing a tangible path to utilizing materials as an additional degree of freedom as compared to historical approaches where materials were considered a constant single minimum

design allowable value throughout the entire volume of a component.

Application of ICME in Support of Advanced Turbine Engine Designs

Pratt & Whitney has used materials and process modeling extensively in the development of nearly all new and soon to be fielded turbine engines. Several examples of materials and manufacturing process modeling and simulation applications include:

1. Fan blade materials and manufacturing processes

2. Disk, shaft and case alloy, forging, heat treatment, joining and machining processes

3. Airfoil alloy and process designs

Fan blade assembly and joining processes. Heavily contoured and often hollow, titanium fan blades provide a unique capability for very high speed fan blade applications. These components are processed by means of complex thermo-mechanical processing to produce the required shape, join components into full assemblies and produce optimum microstructure to produce the desired performance capabilities, including strength, stiffness and fatigue.

Pratt & Whitney employs materials and process modeling to support structural and thermal analyses of manufacturing equipment, tooling systems and components for a range of critical fan blade manufacturing processes including forging, linear friction welding (both OEM and repair processes), inertia friction welding, diffusion bonding and forming of hollow fan blades.

The forging of titanium alloys can produce strain induced porosity (SIP) if local strains and strain rates are not carefully controlled. SIP is of concern in titanium gas turbine engine components because it can act as the site for fatigue crack initiation and significantly impact part durability. At P&W, studies have been performed to correlate strain and strain rates as a function of temperature on the formation of SIP. These studies were conducted using interrupted tensile tests to document the level SIP formed for a given strain rate and strain. The tensile test was modeled using DEFORM™ to establish a correlation between porosity area fraction and a model defined material damage parameter. Once established, the predicted damage parameter was applied to the development of deformation processes for titanium gas turbine engine components to provide component location-specific understanding of SIP formation. Figure 5 shows the predicted damage parameter

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for various locations along the length of a Ti6-4 tensile specimen. Also shown is the observed post test porosity levels, which were measured using image analysis techniques.

Figure 5. DEFORM™ prediction of damage parameter during a tensile test of a Ti6-4 specimen (A). Also shown is the observed post-test porosity level (B). Image analysis was used to quantify the level of porosity. DEFORM is a trade mark name of the Scientific Forming Technologies Corporation.

Advanced application of linear friction welding modeling and simulation has resulted in robust OEM manufacturing processes and maturing repair processes for these high cost, critical assemblies. Pratt & Whitney uses the linear friction welding (LFW) process to manufacture Integrally Bladed Rotors (IBRs) by friction welding blades onto hubs. The blade is oscillated as a normal or forge load is applied to the weld surfaces, resulting in frictional heating of the surfaces and material flows or "upsets". The oscillation ceases once a target upset is achieved and the

material is allowed to cool under the forge load. The resulting weld has material properties equal to or better than those of the parent materials. Accurate prediction of thermal conditions, strain, and final upset based on the controlled input material enabled establishment of a robust, repeatable manufacturing process.

LFW repair process development introduced the additional challenge of needing to support finished hub and stub geometries without causing any damage to critical finished surfaces. Significant effort had been invested into developing methods to meet these challenges. LFW process simulation has also been performed to gain insight into material flow and final weld surface geometry and has lead to successful deployment of this technology into the field.

In addition to the assessment and optimization of metal flow, bonding and final geometry; microstructure and mechanical property models have been applied to various fan components in advanced engines. It is well known that the fatigue properties of alpha-beta titanium alloys are closely linked to microstructure, including size, morphology and volume fraction of phases, and crystallographic texture. Tools have been developed and deployed which predict the evolution of titanium microstructure on a location-specific basis during manufacture, leading to a location-specific understanding of component properties during the design phase. Pratt & Whitney has developed mechanistic, microstructure-sensitive models that link microstructure of alpha-beta titanium alloys to final mechanical properties, such as fatigue. Figure 6 shows an actual versus predicted plot for Ti6-4 high cycle fatigue strength for various stress ratios. This model predicts fatigue strength very accurately based on microstructural constituent phase size, quantity, and texture.

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Figure 6. Plot show a comparison of actual versus predicted high cycle fatigue strength for ΤΪ6-4 based on a microstructure-sensitive materials model.

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Disk material and process modeling. At Pratt & Whitney, material and process modeling of disks includes a number of deformation processes (e.g. forging, extrusion and powder compaction), heat treat processes, joining, machining distortion simulation, microstructure evolution, mechanical property prediction and advanced alloy development.

Disk forging process modeling is applied to a wide range of materials and manufacturing processes, including powder, and conventional cast and wrought alloys by isothermal or conventional press processing. Modeling is used to understand material flow, strain, strain rate and temperature distribution throughout forging processes. Figure 7 shows a typical DEFORM™ simulation prediction of temperature distribution within a commercial engine IN718 high turbine disk forging during a preliminary preform forging operation. Simulations such as this are used to ensure that the die cavity is completely filled, forging defects do not occur, die loading and stresses do not exceed design limits, and the proper temperature, strain and strain rates are achieved to deliver the desired final microstructure. Materials models are often linked to the continuum process models to provide location-specific microstructure predictions. These in turn can then be used as inputs to subsequent mechanical property models to support design optimization.

Temperature ( X )

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Figure 7. DEFORM™ simulation prediction of the temperature distribution within a commercial engine 1N718 turbine disk forging.

Modeling of the powder consolidation process for powder metallurgy alloys is used to predict relative density level during the compaction process. Extrusion modeling of compacted powder alloys is used to understand strain, temperature and die loading. Tracking the spatial location and orientation of particles (individual point tracking or

included secondary objects) is done with varying types of deformation process models.

Disk heat treat process modeling is also applied to isothermal powder and conventional cast and wrought alloy components. Typical applications include alloy and process development, as well as support of design and manufacturing process development and approval. Modeling is used to evaluate heat-up and cooling rates, understand and avoid thermal stress induced cracking, and understand residual stress and distortion during the heat treat process. Figure 8 shows an example of a quench crack prediction for a commercial engine high turbine disk. This figure shows the ratio of predicted thermally driven stress to the material strength value. A pragmatic criterion of one indicates a risk of formation of a quench crack. This type of model can be used to optimize the quench process and part shape to minimize the risk of quench cracking. Figure 9 shows an example of residual stress prediction resulting from the heat treatment of a GTF engine high pressure turbine disk side plate.

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Figure 8. Prediction of quench cracking risk for a commercial engine turbine disk. The plot shows the location-specific prediction of quench cracking parameter.

The prediction of local cooling rate also enables the prediction of microstructure evolution and subsequent prediction of location-specific properties. Figure 10 shows an example of predicted PrecipiCalc secondary gamma-prime size distribution throughout the cross-section of a nickel-base superalloy disk. [3]. Figure 11 shows the corresponding contours of predicted yield strength.