中國(guó)有色金屬學(xué)報(bào)(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 22 No. 6 June 2012 |
（1. Industrial Training Centre, Harbin Engineering University, Harbin 150001, China;
2. College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001, China）
Abstract:The as-cast ingot of equiatomic nickel-titanium shape memory alloy (NiTi SMA) was prepared by vacuum consumable arc melting. The tensile tests and the compressive tests with respect to as-cast NiTi SMA were performed to study its mechanical properties of fracture. The microanalysis of as-cast NiTi SMA as well as its fractured samples was performed so as to better understand microstructure evolution and fracture behavior of NiTi SMA. Under tensile loading, the as-cast NiTi SMA shows higher plasticity and is characterized by ductile fracture at 750 °C, but it demonstrates poorer plasticity and is characterized by cleavage fracture as well as transcrystalline fracture at room temperature and -100 °C. Under compressive loading at -100 °C, the as-cast NiTi SMA is characterized by shear fracture where the normal to the shearing fracture surface inclines about 45° to the compressive axis, and belongs to cleavage fracture where the cracks expand via transcrystalline fracture.
Key words: NiTi alloy; shape memory alloy; as-cast NiTi; microstructural evolution; fracture behavior
