热变形对TiNi形状记忆合金丝材力学性能以及超弹性的影响

Effect of Hot Drawing Process on Mechanical Properties and Superelasticity of TiNi Shape Memory Alloy Wires

通过拉伸测试Ф0．61mmTi-50．8at％Ni合金丝材退火后热拉拔过程中不同直径丝材的力学性能和弹性性能，研究了热变形对TiNi形状记忆合金丝材力学性能及超弹性的影响规律。结果表明，经过650℃退火后Ti-50．8at％Ni合金丝材超弹性较差，而断裂伸长率达50％以上。随着热拉拔变形量增大，超弹性逐渐提高，而塑性迅速降低，当热拉拔总热变形量达50％时，丝材可以获得优良的超弹性能，△σ值（Rell-ReL）为200-250MPa，残余应变小于0．1％。同时伸长率大于10％。

Through hot drawing Ф0.61 mm Ti-50.Sat% Ni alloy after annealing, The mechanical properties and superelasticity of TiNi shape memory alloy wires （from Ф0.61 mm to Ф0.31 mm） were tested by tensile test. The effect rule of hot drawing process on the mechanical properties and superelasficity of the wires was studied. The results show that Ti-50.Sat%Ni alloy wires after annealing at 650℃ have poor superelasticity, while fracture is elongation greater than 50%. With the increase of total plastic deformation of hot drawing, the superelasticity improves, and the plasticity de- creases, when the total plastic deformation of the wires is up to 50%, the values of △σ vary from 200 to 250 MPa, the remaining strain is less than 0.1%, and the elongation is greater than 10%, which obtains excellent elongation and superelasticity.