中國有色金屬學(xué)報(bào)(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 34 No. 10 October 2024 |
（1. International Joint Laboratory of Advanced Nanomaterials of Heilongjiang Province, College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001, China;
2. Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, 141980, Dubna, Russia;
3. Center of Testing and Analysis, College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001, China）
Abstract:The effect of age hardening on the microstructure, martensitic transformation behavior, and shape memory properties of the (Ni50Ti30Hf20)95V5 alloy was investigated by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, differential scanning calorimetry, microhardness, and bending tests. The results demonstrate a significant influence of V addition on the microstructure of the alloy. V addition leads to the formation of a (Ni,V)2(Ti,Hf)-type Laves phase, which coexists with B19'''' martensite at room temperature. Aging at 550 °C results in precipitation hardening due to the formation of nano-scale orthorhombic H-phase, with the peak hardness observed after 3 h of aging. The alloy at peak hardness state exhibits higher transformation strain and lower unrecovered strain compared to the solution-treated sample. The aged sample achieves a maximum transformation strain of 1.56% under 500 MPa.
Key words: shape memory alloys; NiTiHfV; H-phase; Laves phase; martensitic transformation
