Investigation on the Effect of Martensitic and Austenitic Structures on Two-Way Shape Memory Strain Value in Ni-Ti Alloys Trained under Bending

مهندسی متالورژی و مواد

Article 6, Volume 22, Issue 1 - Serial Number 3, January 2012   

Document Type: Original Articles

DOI: 10.22067/ma.v22i1.10821

Authors

zohre balak^* ; s. mehdi Abasi

Abstract

In this article, the influence of martensitic and austenitic structures on two-way shape memory strain in two Ni-Ti alloys with 49.9 and 50.5 at% Ti trained by bending were investigated. The samples prepared with VIM (Vacuum Induction Melting) were trained in martensitic and austenitic conditions by applying bending deformation. The effects of pre-strain level and number of training cycles in martensitic and austenitic conditions were also studied. The results showed that the two-way shape memory strain in the Ni-rich alloy is greater than that of the Ti-rich alloy. In addition, it was observed that training the martensitic microstructure results in higher two-way shape memory strain when compared to the austenitic structure. The pre-strain values of 16.7 and 12.5 % and the optimum training cycles of 10-15 and 15-25 were obtained for the cases of martensitic and austenitic structures, respectively