【摘要】 本文用电阻法、X 射线衍射和透射电镜技术研究了约束加热温度对近等原子比 NiTi 合金相变行为的影响。结果表明,合金的相变行为随约束加热温度的不同而有显著差异。未经约束加热的试样中仅发生马氏体相变,经100℃和450℃约束加热后,在发生马氏体相变前分别发生无公度相变和 R 相变,而经550℃约束加热后,则仅发生马氏体相变。文中分析了上述相变行为的内在原因,并指出与不同约束加热温度下所发生的内应力场有关。更多还原

【Abstract】 The effect of constraied-heating temperature on the transformation beh avior in a near-equiatomic NiTi alloy has been studied by means of electr- ical resistance measurement,X-ray diffraction and TEM techniques.It is show that the transformation behavior of the alloy is remarkably influenced by the constrained-heating temperature.Only martensitic transformation occurs on heating or cooling in the sample without constrained-heating.But the incommensurate transformation and R transformation appear before the mart- ensitic transformation on cooling in the sample constrained-heating at 100℃ and 450℃ respectively.The transformation behavior is the same as that of the sample without constrained-heating when increasing the constrained-he- ating temperature to 550℃.The cause for the difference of the transformat- ion behavior has been discussed and is believed to be mainly related to the characteristics of the initial stress field induced by constrained-heating in the parent phase.更多还原