最新色国产精品精品视频,中文字幕日韩一区二区不卡,亚洲有码转帖,夜夜躁日日躁狠狠久久av,中国凸偷窥xxxx自由视频

Research progress on the Ni-Ti-Pd and Ni-Ti-Pt high temperature shape memory alloys at home and abroad in recent years were reviewed, and the effect of chemical composition, thermal mechanical treatment and the training process on martensitic transformation, high temperature performance of one-way and two-way shape memory effect, and functional stability during repeated thermomechanical cycling of high temperature shape memory alloy were analyzed.The results show that the transformation temperature, the width of transformation hysteresis, high temperature martensitic transformation induced plasticity, creep behaviour, and high temperature thermal cycling properties, were significantly affected by the microstructures.The refinement of grain structure were achieved by the addition of Sc, Cu, or B elements, and cold rolling followed by annealling treatments, and the fine dispersed precipitaties of Ti₂Ni and Ti₂(Ni,Pd) distributed in the matrix were produced by solid solution and aging, and these microstructures were beneficial to the improvement of the high temperature shape memory properties, by the effect of solid solution hardening and precipitation hardening.The preferentially oriented martensite variants, nucleated on the dislocation arrays with the specific stress field obtained during the training under a constant stress, were found to improve the one-way and two-way shape memory properties, and improve the stability of the functional properties and size of the high temperature shape memory alloys.