Effect of cooling rate on the phase transformation behavior and mechanical properties of Ni-rich NiTi shape memory alloy

• Published in: Journal of alloys and compounds 2009-02, Vol.469 (1), p.164-168
• Main Authors: Motemani, Y., Nili-Ahmadabadi, M., Tan, M.J., Bornapour, M., Rayagan, Sh
• Format: Article
• Language: English
• Subjects: Af temperature; Austenite; Condensed matter: structure, mechanical and thermal properties; Cooling rate; Cross-disciplinary physics: materials science; rheology; Differential scanning calorimetry; Elasticity, elastic constants; Exact sciences and technology; Martensite; Martensitic transformations; Materials science; Mechanical and acoustical properties of condensed matter; Mechanical properties of solids; NiTi shape memory alloy; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Physics
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2008.01.153

TiNi alloy is a well-known shape memory alloy and has been widely used for bio-medical, mechanical and electrical applications. In this study, a Ni-rich NiTi alloy was prepared by vacuum arc melting in a water-cooled copper crucible. Three samples of this alloy were heated to 1000 °C and cooled in three media: furnace, water, and dry-ice bath. Differential scanning calorimetry (DSC), X-ray diffraction (XRD), hardness measurement and tensile test were carried out to investigate the effect of cooling rate on transformation temperature and mechanical properties. The results show that Ni 3Ti intermetallic compounds have a great influence on martensitic phase transformation temperature. These tests clearly showed the correlation between cooling rate and properties of the alloy.