Vasile COJOCARU, Doina RĂDUCANU, Ion CINCA, Nicolae … · 20% perhidrol 5 150 10 9 Vibropolisare Buehler MicroFloc Buehler Colloidal Silica 0.02μm + 20% perhidrol 600 - - Buehler

Vasile Dănuț COJOCARU, Doina RĂDUCANU, Ion CINCA,

Nicolae ȘERBAN, Mariana Lucia ANGELESCU, Elisabeta Mirela COJOCARU

Synopsis:

- GUM-type titanium alloys;

- GUM-type titanium alloy synthesis, TM-SPD processing

and characterization;

- Results and conclusions:

TM processing;

SPD processing;

Shot-Peening processing.

GUM-type titanium alloys

GUM-type alloy (typically Ti–Nb–Ta–Zr + oxygen): unique associated properties

of high strength, low elastic modulus and large elastic strain.

Materials for the biomedical domain: demands superior corrosion resistance,

biochemical compatibility and mechanical biocompatibility:

- corrosion resistance (monophasic / biphasic materials);

- biochemical compatibility (obtained by alloying titanium with beta-

stabilizing elements, such as Nb, Ta, Mo, and Zr – which are non-toxic for the

human body);

- mechanical biocompatibility (good mechanical resistance properties,

primarily high strength and high fatigue resistance, accompanied by a low

elastic modulus);

GUM-type titanium alloy synthesis,

TM-SPD processing and characterization

General considerations concerning investigated alloy

M. Morinaga, Y. Murata, H. Yukawa: Molecular orbital approach to

alloy design; Applied Computational Materials Modeling - Theory,

Simulation and Experiment (eds G. Bozzolo, R.D. Noebe, P.B. Abel),

Springer, 2007

Using Morinaga and Yukawa approaches, as

compositional range for the alloying elements

the following composition was computed:

GUM-type titanium alloy:

Ti-31.7Nb-6.21Zr-1.4Fe-0.16O (wt%):

𝑀𝑑 = 2.45; 𝐵𝑜 = 2.87;

where: 𝑀𝑑 – represents the energy level of “d”

orbitals; 𝐵𝑜 – represents the bond order.

𝑀𝑑 = 𝑥𝑖 ∙ 𝑀𝑑𝑖

𝐵𝑜 = 𝑥𝑖 ∙ 𝐵𝑜𝑖



FiveCeles MP25 (Ti: 1.660°C; Nb: 2.468°C; Zr: 1.855°C; Fe: 1.538°C)

GERO SR 100x500 heat treatment oven

Mario di Maio

LQR120AS

rolling-mill



Metkon Digiprep ACCURA

Etapa Disc folosit Mediu de lucru Timp [min] Viteza rotatie [rpm] Forta [N]

1 Metkon Abrasive paper-P800 Apa 3 - 5 300 20-30



4 Metkon Textile disk - FEDO-3 Metkon DIAPAT 3μm 2 - 4 150 20-30

5 Metkon Textile disk - FEDO-3 Metkon DIAPAT 3μm 2 - 4 150 10-15

6 Metkon Textile disk - FEDO-1 Metkon DIAPAT 1μm 5 150 10

7 Metkon Textile disk - FEDO-1N Metkon DIAPAT 0.25μm 5 150 10

8 Metkon Textile disk - METAPO-VMetkon Colloidal Silica 0.05μm +

20% perhidrol5 150 10

9Vibropolisare

Buehler MicroFloc

Buehler Colloidal Silica 0.02μm +

20% perhidrol600 - -

Buehler VibroMet2



Tescan VEGA II-XMU SEM

Panalytical

XPert3 MRD

Gatan MICROTEST 2000

Willson-Volpert

401MVA



Distribution of alloying elements in Ti-31.7Nb-6.21Zr-

1.4Fe-0.16O (wt%) alloy after synthesis

ElementCompoziție

[% greutate]

Compoziție

[% atomice]

Eroare

absolută

[%]

Eroare

relativă

[%]

Titan 60,1603 73,6959 1,6146 2,1909

Niobiu 31,7612 20,0467 0,6400 3,1925

Zirconiu 6,5123 4,1859 0,1270 3,0340

Fier 1,4028 1,4728 0,0557 3,7819

Oxigen 0,1634 0,5987 0,0861 14,3812

Suma 100 100

Obtained chemical composition of

Ti-31.7Nb-6.21Zr-1.4Fe-0.16O (wt%) alloy

XRD spectra of Ti-31.7Nb-6.21Zr-1.4Fe-0.16O (wt%) alloy

after synthesis

Results and conclusions

TM processing


TM processing

ST - 800°C 45 - 50 [µm] Polyhedral equiaxed grains



SEM-BSE image of ST1 SEM-BSE image of ST2 SEM-BSE image of ST3


TM processing

Microstructural state

Ultimate tensile

strength

sUTS [MPa]

Yield strength

s0.2 [MPa]

Elongation to

fracture

ef [%]

Elastic modulus

E [GPa]

ST – 800°C 1083 486 9 68

ST – 900°C 896 424 8 64

ST – 1000°C 828 428 5 69

Strain-stress diagram for ST1



Best candidate for TM processing


SPD processing


SPD processing

SEM-BSE image of ST1: RD-ND; TD-ND; RD-TD





SPD processing

State

Ultimate tensile

strength

sUTS [MPa]

Yield strength

s0.2 [MPa]

Elongation to

fracture

ef [%]

Elastic modulus

E [GPa]

ST 1 1090,9 670,3 13,1 66,2

ST 2 1254,6 684,1 15,2 64,1

ST 3 1240,4 696,2 9,9 65,3

ST 4 1217,5 715,7 3,9 67,6

Strain-stress diagrams for ST1 – ST4

Best candidate for SPD processing

TM – SPD processing route


TM-SPD processing

Results and conclusionsTM-SPD processing

Microstructural state 1




Microstructural

state

Ultimate tensile

strength

sUTS [MPa]

Yield strength

s0.2 [MPa]

Elongation to

fracture

ef [%]

Elastic modulus

E [GPa]

State 1 830±14.6 335±7.9 19,1±3.2 59±4,6

State 2 896±15.1 424±9.7 8,4±3.1 64±3,5

State 3 1254±24.7 684±8.2 15,2±2.3 64±2,3




TM-SPD processing

Results and conclusionsShot-Peening processing

Ball-surface interaction

Shot-peening

processing

scheme

SampleBall diameter

[mm]

Shot-peening density

[impacts/cm2]

Sample 1 1,0 150.000

Sample 2 1,6 58.000

Sample 3 2,0 29.000

Sample 4 1,0 300.000

Sample 5 1,6 116.000

Sample 6 2,0 58.000


SEM-EBSD map of

precursor surface

Grain-size distribution

of precursor surface

XRD spectra of precursor surface


SampleBall diameter

[mm]

Influence depth

[m]

Sample 1 1,0 110

Sample 2 1,6 200

Sample 3 2,0 220

Sample 4 1,0 180

Sample 5 1,6 220

Sample 6 2,0 260

SEM-EBSD image of Sample 3 processed surface




SampleBall diameter

[mm]

Influence depth

[m]

Sample 1 1,0 110

Sample 2 1,6 200

Sample 3 2,0 220

Sample 4 1,0 180

Sample 5 1,6 220

Sample 6 2,0 260





SampleBall diameter

[mm]

Influence depth

[m]

Sample 1 1,0 110

Sample 2 1,6 200

Sample 3 2,0 220

Sample 4 1,0 180

Sample 5 1,6 220

Sample 6 2,0 260

XRD spectra of Sample 3 vs. Sample 6




SEM-EBSD image of Sample 6 microstructure

Grain-refinement process during shot-peening

ACKNOWLEDGEMENTS

This work was supported by a grant of the Romanian National Authority for Scientific Research, Executive Unity for Higher Education Financing, Research, Development and Innovation, Collaborative Project No. 213/2014 (2014–2016) and No. 112PED/2017 (2017-2018)

REFERENCES:

D. Raducanu, V.D. Cojocaru, A. Nocivin, I. Cinca, N. Serban, E.M. Cojocaru.

Contributions to Mechanical Characteristics Improvement of Some Biomedical TNTZ

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ISSN 1047-4838, DOI:10.1007/s11837-018-3091-x;

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A. Nocivin, V.D. Cojocaru, D. Raducanu, I. Cinca, M.L. Angelescu, I. Dan, N. Serban,

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http://dx.doi.org/10.1007/s11837-018-3091-x

http://dx.doi.org/10.3390/met8050297

http://dx.doi.org/10.1007/s11665-017-2863-8

http://dx.doi.org/10.1007/s12613-017-1477-3

REFERENCES:

Thank you for attention !

Documents

Vasile COJOCARU, Doina RĂDUCANU, Ion CINCA, Nicolae … · 20% perhidrol 5 150 10 9 Vibropolisare Buehler MicroFloc Buehler Colloidal Silica 0.02μm + 20% perhidrol 600 - - Buehler