Effect of annealing on the microstructures and deformation behaviour of Ti–50.7at.%Ni shape memory alloy. (April 2016)

• Record Type: Journal Article
• Authors: Hastuti, Kurnia; Hamzah, Esah; Hashim, Jasmi
• Is Part Of: Proceedings of the Institution of Mechanical Engineers. Volume 230:Number 2(2016:Apr.)
• Page Start: 436
• Page End: 445
• Publication Date: 2016-04
• Subjects: Shape memory alloy -- annealing temperature -- deformation behaviour -- superelasticity; Materials -- Periodicals; Engineering design -- Periodicals; 620.11
• DOI: 10.1177/1464420715577150
• Languages: English
• ISSNs: 1464-4207

Abstract

In this paper Ti–50.7at.%Ni as a commercial material was examined to analyse the effect of annealing temperature on the microstructure and deformation behaviour. It was found that the microstructure and deformation behaviour of as-received material was affected by the existence of dislocations that was introduced during manufacturing process. The presence of martensite variant and the B2 austenite broadening in XRD spectra of as-received material verified this conclusion. However, annealing treatment has gradually eliminated this effect. The plateau region on stress–strain curve which was absent in the as-received material started to appear and get longer with increasing annealing temperature. Maximum tensile strength was observed in the sample annealed at 400 ℃ for 1 h. Annealing treatment above 500 ℃ transformed the B19′ martensite to B2 austenite, which leads to a decrease in the tensile strength of the material. Nearly perfect superelasticity was found in the as-received material and sample annealed at 300 ℃.