日本金属学会誌

J. Japan Inst. Metals, Vol. 69, No. 8 (2005),
pp. 568-574

Effect of Pre-Strain on Transformation and Deformation Behavior in Ti-50 at%Ni Shape Memory Alloy

Toshio Sakuma1,, Yuji Mihara2,, Yasuo Ochi2 and Kiyoshi Yamauchi3

1Central Research Institute of Electric Power Industry
2University of Electro-Communications
3Tohoku University

Abstract:

In many cases that shape memory alloys are applied to the engineering and medical fields, it is necessary to deform them in martensitic phase. However, if the slip-deformation occurs, shape recovery does not occur completely even if heated up above Af. It is reported that transformation temperatures are changed by pre-deformation and in constrained strain condition. Therefore, it is important to investigate the relationship between the pre-deformation and the deformation and transformation characteristics such as recovery stress, transformation temperatures and so on. The purpose of this work is to clarify the influence of pre-deformation on recovery strain, recovery stress and transformation temperatures in a Ti-Ni alloy. The specimens are Ti-50 at%Ni annealed at 1103 K for 60 s. The variation of recovery strain, recovery stress and transformation temperatures by pre-straining is investigated experimentally. The variation of transformation and deformation behavior by pre-straining will be discussed in relation to the volume fraction of slip-deformed martensite.


(Received 2005/2/22)

Keywords:

shape memory alloy, Ti-Ni alloy, pre-strain, recovery stress, recoverable strain, transformation temperature, volume fraction of slip-deformed martensite


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