Hot Rolling and Ageing Effect on the Pseudoelasticity Behaviour of Ti-Rich TiNi Shape Memory Alloy

Narendranath. S., Vijay Desai, S. Basavarajappa, K.V. Arun, S. Manjunath Yadav

Department of Mechanical Engineering, National Institute of Technology, Srinivasanagar,Surathkal, Karnataka, India.
Department of Studies in I & P Engineering, University B D T College of Engineering,Davanagere-577 004 India.
Department of Studies in Mechanical Engineering, University B D T College of Engineering, Davanagere-577 004 India.

DOI: 10.4236/jmmce.2010.94025                

Abstract

This paper presents the findings of an experimental study of how ageing temperature affects the pseudoelasticity (PE) and its phases of Shape Memory Alloy (SMA). These have been examined by means of tensile testing machine and X-ray diffraction (XRD). By increasing the ageing temperature (constant ageing time) from 350oC to 550oC critical stress for martensite formation and psuedo-elastic elongation increased. However, specimen aged at 650oC showed a decrease in the critical stress for martensite formation and psuedo-elastic elongation. After second and third sequence of loading and unloading, the critical stress shifted towards higher side was observed. The XRD measurement revealed that phases present in the matrix drastically changes with ageing temperatures. Transformation was taking place in two-way transformation, i.e., during heating martensite (B_19') transformed to austenite (B₂) while cooling the austenite (B₂) transformed back to martensite (B_19') .

Keywords

Pseudoelasticity; S M A; Critical stress; Elongation

Conflicts of Interest

The authors declare no conflicts of interest.

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