系统研究了低Nb含量(原子分数为4.5%)的Ni-Ti-Nb形状记忆合金的微 观组织形态和相变特征以及预变形对相变滞后的影响. 结果表明, Ni/Ti比的微小变化对合 金的微观组织产生重要影响, 从而影响合金的相变特征. 低Nb含量的Ni-Ti-Nb形 状记忆合金仍然具有宽滞后效应. 研究了在相同温度下分别处于马氏体和奥氏 体状态时低Nb合金的变形行为, 并结合热弹性马氏体相变动力学作了相关解释.
The structure evolution and phase transformation behavior of Ni-Ti-Nb shape memory alloys with 4.5%Nb (atomic fraction) were studied systematically. It is found that the structure evolution as well as the phase transformation characteristics of the alloys is very sensitive to the ratio of the atomic fractions of Ni and Ti. After appropriate predeformation, a wide hysteresis was observed in such low Nb alloys. The difference of the mechanical behaviors of the alloys with austenite or martensite states was investigated at the same temperature, and explained by the kinetics of thermoelastic martensitic transformation.