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TAMU-UIB collaboration: TAMU-UIB collaboration:
characterization of Ni-Ti-Zr and Ni-Ti-Hf characterization of Ni-Ti-Zr and Ni-Ti-Hf
high temperature shape memory alloyshigh temperature shape memory alloys
TAMU-UIB collaboration: TAMU-UIB collaboration:
characterization of Ni-Ti-Zr and Ni-Ti-Hf characterization of Ni-Ti-Zr and Ni-Ti-Hf
high temperature shape memory alloyshigh temperature shape memory alloys
A. Evirgen1, I. Karaman1, R. Santamarta2, J. Pons2
1. Dept. of Mechanical Eng., Texas A&M University, TX, USA
2. Dept. of Physics, Univ. Balearic Islands, Palma de Mallorca, Spain
jaume.pons@uib.es
Activity in the framework of IIMEC in 2011Activity in the framework of IIMEC in 2011Activity in the framework of IIMEC in 2011Activity in the framework of IIMEC in 2011
PhD Student Exchange Activity: TAMU – UIB
Summer research stay of ALPER EVIRGEN (I. Karaman’s PhD
student) in UIB. July 2011 Financed by IIMEC
Research topic:
Study of (Ni-rich) Ni-Ti-Zr and Ni-Ti-Hf HTSMAs
jaume.pons@uib.es
Activity in the framework of IIMEC in 2011Activity in the framework of IIMEC in 2011Activity in the framework of IIMEC in 2011Activity in the framework of IIMEC in 2011
PhD Student Exchange Activity: TAMU – UIB
Summer research stay of ALPER EVIRGEN (I. Karaman’s PhD
student) in UIB. July 2011 Financed by IIMEC
Research topic:
Study of (Ni-rich) Ni-Ti-Zr and Ni-Ti-Hf HTSMAs
NiTi: TM ~ 80ºC Increase of Ni content → TM drops
Substitution of Ti by Hf or Zr raises TM (Ti+Hf/Zr)-rich ternary alloys
Recently, study of Ni-rich ternary alloys
High industrial interest (automotive, aerospace, …)
jaume.pons@uib.es
Activity in the framework of IIMEC in 2011Activity in the framework of IIMEC in 2011Activity in the framework of IIMEC in 2011Activity in the framework of IIMEC in 2011
jaume.pons@uib.es
MaterialsMaterialsMaterialsMaterials
Materials: Selected in TAMU
Ni50.3Ti34.7Zr15 15Zr (at%)
Ni50.3Ti29.7Zr20 20Zr
Ni50.3Ti34.7Hf15 15Hf
Hot extruded (900ºC)
Solution Heat Treatment: 900oC, 1h + WQ (SHT)
jaume.pons@uib.es
Collaboration planCollaboration planCollaboration planCollaboration plan
“Macroscopic” characterization of
functional properties
DSC
Thermal cycling under stress
Thermal treatments to
improve functional properties
Alper’s PhD
Microstructural characterization
TEM, HRTEM
EDX
Most of observations
performed during Alper’s stay
Afterwards: Analysis of results
jaume.pons@uib.es
General ResultsGeneral ResultsGeneral ResultsGeneral Results
VERY FRUITFUL ACTIVITY:
Education:
Intense immersion in practical TEM/HRTEM work
(preparation of samples and observations)
Personal life:
Stay in a country with different culture
Collaboration:
Strong impulse to TAMU-UIB collaboration
Scientific:
Good results suitable for several publications
jaume.pons@uib.es
Scientific ResultsScientific ResultsScientific ResultsScientific Results
As extruded and Solution Heat Treated state
Low TM temperatures and poor reproducibility
Thermal treatments to improve the alloy
performance
20Zr
15Hf
jaume.pons@uib.es
Scientific ResultsScientific ResultsScientific ResultsScientific Results
20Zr DSC results
jaume.pons@uib.es
Scientific ResultsScientific ResultsScientific ResultsScientific Results
15Hf DSC results
jaume.pons@uib.es
Scientific ResultsScientific ResultsScientific ResultsScientific Results
20Zr Furnace cooling from 700ºC to 100ºC in 48h
jaume.pons@uib.es
Scientific ResultsScientific ResultsScientific ResultsScientific Results
15Hf SHAPE MEMORY EFFECT
10h at 550ºC
~ 2.5%
jaume.pons@uib.es
Scientific ResultsScientific ResultsScientific ResultsScientific Results
Microstructural observations in aged samples
Precipitation of a new phase
Ni-rich NiTi Ni4Ti3 or Ni3Ti Not in ternary alloys
jaume.pons@uib.es
15Zr 200h at 500ºC Austenite at RT
Lenticular precipitates in austenitic matrix. ~ 20 nm
Scientific ResultsScientific ResultsScientific ResultsScientific Results
TEM HRTEM
jaume.pons@uib.es
The precipitates show an enhanced contrast every three 011 planes and extra spots in the diffraction patterns. They are fully coherent with austenitic matrix.
Scientific ResultsScientific ResultsScientific ResultsScientific Results
15Zr 200h at 500ºC Austenite at RT
jaume.pons@uib.es
15Hf 10h at 450ºC Austenite at RT
Nanometric precipitates (~5 nm)
Scientific ResultsScientific ResultsScientific ResultsScientific Results
jaume.pons@uib.es
20Zr 48h at 500ºC
Scientific ResultsScientific ResultsScientific ResultsScientific Results
15Hf 3h at 500ºC
Precipitates in martensite
jaume.pons@uib.es
20Zr 700ºC-100ºC FC
Long precipitates O(100 nm)
Scientific ResultsScientific ResultsScientific ResultsScientific Results
jaume.pons@uib.es
EDX Microanalysis
Scientific ResultsScientific ResultsScientific ResultsScientific Results
15Hf 10h at 600ºC
20Zr 700ºC-100ºC FC
at% Ni Ti Hf Precipitates 52.5 21.2 26.3 Matrix 49.2 34.0 16.8
at% Ni Ti Zr Precipitates 52.6 18.8 28.6 Matrix 49.6 30.8 19.6
Precipitates are richer in Hf/Zr and poorer in Ti, and a bit richer in Ni.
jaume.pons@uib.es
Twinning modes of B19’ martensite in samples with precipitates
Scientific ResultsScientific ResultsScientific ResultsScientific Results
jaume.pons@uib.es
Twinning modes of B19’ martensite in samples with precipitates
Scientific ResultsScientific ResultsScientific ResultsScientific Results
(011)B19’ Type I twinning Twin plane || intervariant boundary
(001)B19’ compound twinning (internal twins - LIS)
Same twinning modes and boundaries as reported in literature for Ni-Ti-Hf alloys
{111} and {113}-type intervariant boundaries
jaume.pons@uib.es
Intervariant boundaries
Scientific ResultsScientific ResultsScientific ResultsScientific Results
{111} or {113}-type boundaries quite irregular
(011)
Perfect (011) boundaries
|| twin plane
jaume.pons@uib.es
Intervariant boundaries
Scientific ResultsScientific ResultsScientific ResultsScientific Results
{111} or {113}-type boundaries quite irregular
(011)
Perfect (011) boundaries
|| twin plane
jaume.pons@uib.es
Structural model of the precipitate new phase
Scientific ResultsScientific ResultsScientific ResultsScientific Results
jaume.pons@uib.es
Benefits received from IIMECBenefits received from IIMECBenefits received from IIMECBenefits received from IIMEC
Benefits in Alper’s education and personal life
The summer stay provided a strong impulse to TAMU-UIB
collaboration
Several good publications envisaged
Creation of a good scientific common background for possible
future applications of research projects in International
Programs (NSF, EU, …)
jaume.pons@uib.es
Thanks for your attention!!!Thanks for your attention!!!Thanks for your attention!!!Thanks for your attention!!!
jaume.pons@uib.es
jaume.pons@uib.es
Scientific ResultsScientific ResultsScientific ResultsScientific Results
15Hf SHAPE MEMORY EFFECT
SHT
~ 3.5%
jaume.pons@uib.es
Scientific ResultsScientific ResultsScientific ResultsScientific Results
20Zr Af temperature vs ageing time
jaume.pons@uib.es
Scientific ResultsScientific ResultsScientific ResultsScientific Results
15Hf Af temperature vs ageing time
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