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Shape memory effect and superelasticity in a strain glass alloy
Yu Wang1, Xiaobing Ren, Kazuhiro Otsuka
1National Insititute for Material Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan.
Physical Review Letters
|December 13, 2006
Summary
Shape memory and superelasticity were observed in a nonmartensitic alloy undergoing a strain glass transition. These effects arise from a stress-induced transformation to a martensitic phase and its reverse, expanding the possibilities for shape memory applications.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Alloy Development
Background:
- Shape memory effect and superelasticity are typically associated with alloys exhibiting spontaneous martensitic transformations.
- The existence of these phenomena in systems lacking martensitic transformation is considered unusual and challenging to achieve.
Purpose of the Study:
- To investigate the possibility of shape memory and superelasticity in a nonmartensitic alloy system.
- To explore the underlying mechanisms responsible for these effects in the absence of conventional martensitic transformations.
Main Methods:
- Utilized a Ti48.5Ni51.5 alloy, which does not undergo a spontaneous martensitic transformation but exhibits a strain glass transition.
- Performed in situ x-ray diffraction experiments to analyze structural changes under stress.
Main Results:
- Demonstrated shape memory and superelasticity effects in the nonmartensitic Ti48.5Ni51.5 alloy.
- Confirmed that these effects originate from a stress-induced transformation from the strain glass phase to a martensitic phase and its subsequent reverse transformation.
Conclusions:
- Shape memory and superelasticity can occur in systems exhibiting a strain glass transition, not solely those with spontaneous martensitic transformations.
- This finding broadens the scope of materials exhibiting shape memory and superelasticity, potentially enabling new technological applications.
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