Details
| Original language | English |
|---|---|
| Pages (from-to) | 16-19 |
| Number of pages | 4 |
| Journal | Materials letters |
| Volume | 159 |
| Publication status | Published - 14 Jun 2015 |
Abstract
Thermal stabilization of martensite in shape memory alloys is known to strongly affect functional properties due to changes in transformation temperatures. As martensite stabilization in many alloys proceeds in an uncontrollable fashion, it has been treated as a detrimental mechanism in the past. In a recent study it was found that martensite stabilization can be controlled by aging of stress-induced martensite, allowing development of a new class of high-temperature shape memory alloys. Symmetry-conforming adaptation of short-range order during thermal treatment has been stated to be the mechanism responsible for this phenomenon. However, direct experimental evidence for changes in short-range ordering has not been presented. The current study has been conducted in order to fill this gap. A Co-Ni-Ga shape memory alloy has been studied by neutron diffraction in different conditions, i.e. as-grown austenite, quenched martensite, heat-treated austenite and stabilized stress-induced martensite. The results obtained unequivocally reveal that martensite stabilization is triggered by a chemical disordering mechanism. Thus, the concept of symmetry-conforming short-range order proposed 1997 by Ren and Otsuka has finally found experimental verification for a Co-Ni-Ga alloy.
Keywords
- High-temperature shape memory alloy, Neutron diffraction, Phase transformation, SIM-aging, Single crystal
ASJC Scopus subject areas
- Materials Science(all)
- General Materials Science
- Physics and Astronomy(all)
- Condensed Matter Physics
- Engineering(all)
- Mechanics of Materials
- Engineering(all)
- Mechanical Engineering
Cite this
- Standard
- Harvard
- Apa
- Vancouver
- BibTeX
- RIS
In: Materials letters, Vol. 159, 14.06.2015, p. 16-19.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Martensite stabilization in shape memory alloys
T2 - Experimental evidence for short-range ordering
AU - Kadletz, Peter M.
AU - Krooß, Philipp
AU - Chumlyakov, Yuri I.
AU - Gutmann, Matthias J.
AU - Schmahl, Wolfgang W.
AU - Maier, Hans J.
AU - Niendorf, Thomas
PY - 2015/6/14
Y1 - 2015/6/14
N2 - Thermal stabilization of martensite in shape memory alloys is known to strongly affect functional properties due to changes in transformation temperatures. As martensite stabilization in many alloys proceeds in an uncontrollable fashion, it has been treated as a detrimental mechanism in the past. In a recent study it was found that martensite stabilization can be controlled by aging of stress-induced martensite, allowing development of a new class of high-temperature shape memory alloys. Symmetry-conforming adaptation of short-range order during thermal treatment has been stated to be the mechanism responsible for this phenomenon. However, direct experimental evidence for changes in short-range ordering has not been presented. The current study has been conducted in order to fill this gap. A Co-Ni-Ga shape memory alloy has been studied by neutron diffraction in different conditions, i.e. as-grown austenite, quenched martensite, heat-treated austenite and stabilized stress-induced martensite. The results obtained unequivocally reveal that martensite stabilization is triggered by a chemical disordering mechanism. Thus, the concept of symmetry-conforming short-range order proposed 1997 by Ren and Otsuka has finally found experimental verification for a Co-Ni-Ga alloy.
AB - Thermal stabilization of martensite in shape memory alloys is known to strongly affect functional properties due to changes in transformation temperatures. As martensite stabilization in many alloys proceeds in an uncontrollable fashion, it has been treated as a detrimental mechanism in the past. In a recent study it was found that martensite stabilization can be controlled by aging of stress-induced martensite, allowing development of a new class of high-temperature shape memory alloys. Symmetry-conforming adaptation of short-range order during thermal treatment has been stated to be the mechanism responsible for this phenomenon. However, direct experimental evidence for changes in short-range ordering has not been presented. The current study has been conducted in order to fill this gap. A Co-Ni-Ga shape memory alloy has been studied by neutron diffraction in different conditions, i.e. as-grown austenite, quenched martensite, heat-treated austenite and stabilized stress-induced martensite. The results obtained unequivocally reveal that martensite stabilization is triggered by a chemical disordering mechanism. Thus, the concept of symmetry-conforming short-range order proposed 1997 by Ren and Otsuka has finally found experimental verification for a Co-Ni-Ga alloy.
KW - High-temperature shape memory alloy
KW - Neutron diffraction
KW - Phase transformation
KW - SIM-aging
KW - Single crystal
UR - http://www.scopus.com/inward/record.url?scp=84933055377&partnerID=8YFLogxK
U2 - 10.1016/j.matlet.2015.06.048
DO - 10.1016/j.matlet.2015.06.048
M3 - Article
AN - SCOPUS:84933055377
VL - 159
SP - 16
EP - 19
JO - Materials letters
JF - Materials letters
SN - 0167-577X
ER -