Effect of annealing temperature on superelastic properties of martensitic transformation of TiNi memory alloy
Effect of annealing temperature on microstructure,martensitic transformation stress,recovery strain,residual strain,absorbed energy,stored energy and dissipation energy of TiNi memory alloy after drawing deformation was studied by means of X-ray diffraction,differential scanning calorimetry,transmission electron microscopy and tensile test.The results show that when the annealing temperature increases from 350 ℃ to 550 ℃,the average grain size of the TiNi memory alloy increases from 15 nm to 400 nm,the martensitic transformation stress decreases from 766 MPa to 115 MPa,the recovery strain decreases from 6.7％to 0.8％,the residual strain increases from 1.3％to 7.2％,the absorbed energy of martensitic transformation decreases from 50.6 MJ/m3 to 8.6 MJ/m3,the stored energy of martensitic transformation decreases from 15.7 MJ/m3 to 0.8 MJ/m3,and the dissipation energy of martensitic transformation decreases from 34.9 MJ/m3 to 8.0 MJ/m3.The analysis suggests that the influence of annealing temperature on the martensitic transformation superelasticity performance of the TiNi memory alloy mentioned above is mainly due to the increase in annealing temperature,which increases the grain size of the TiNi memory alloy and reduces the density of grain boundaries,thereby reducing the resistance of alloy stress induced martensitic transformation and affecting its superelasticity performance.
TiNi memory alloymartensitic transformationannealing temperaturesuperelasticity
NETL
NSTL
万方数据
