The deformation behavior of TiNi shape memory alloy under axial dynamic compression

• Published in: Journal of Wuhan University of Technology. Materials science edition 2004-09, Vol.19 (3), p.86-89
• Main Authors: Huang, Xue-Wen, Dong, Guang-Neng, Zhou, Zhong-Rong, Xie, You-Bai
• Format: Article
• Language: English
• Subjects: Alloys; Axial compression; Deformation; Dynamic loads; Martensitic transformations; Metallurgy; Nickel base alloys; Nickel compounds; Pseudoelasticity; Shape memory alloys; Strain rate; Titanium compounds
• ISSN: 1000-2413; 1993-0437
• DOI: 10.1007/BF02835070

The deformation behavior of Ti-50.9 at % Ni shape memory alloy under axial compression dynamic loads was investigated by an MTS 858 Mini Bionix test machine. The alloy were aged at 500°C for an hour before being machined into specimens. The compression experiments were conducted at 20°C and the variety of dynamic loads were controlled by the strain rate, which was 3 mm/min, 15 mm/min, 30mm/min and 50 mm/min, respectively. The experimental results indicate that in the case of 3 mm/min, stress-induced martensitic transformation occurs at about 350 MPa when loading and reverse transformation at about 200 MPa when unloading, during which the aged Ti-50.9 at % Ni alloy shows the recoverable nonlinear pseudoelastic strain of 4.3% with the residual strain of 1.2% reserved. With the strain rate increasing, the area encloses by loading-curve and unloading-curve, i.e stress (strain) hysteresis becomes smaller and smaller and the residual strain also decreases, while critical stress for inducing martensitic transformation rises. At a higher strain rate the alloy exhibits linear-like pseudoelasticity, which is up to 4.5%.[PUBLICATION ABSTRACT]