应力引起的镍钛单晶形状记忆合金相变的实验研究

在单晶形状记忆合金试样中，由于没有晶粒之间的约束，它的马氏体相界面移动比多晶容易，用实验方法研究其相变的特点，对建立新的理论模型有意义，因而对它的实验分析显得重要。本文利用高分辨率的CCD系统监测到NiTi单晶形状记忆合金在拉伸时的相变伪弹性的过程；利用X射线衍射法得到了NiTi单晶试样在拉伸方向的晶向；运用高分辨率的云纹干涉技术，获得了应力引起的NiTi单晶形状记忆合金相变时的变形场；利用高分辨率、高灵敏度的红外相机记录了NiTi单晶在拉伸状态下的温度变化规律；对低温下NiTi单晶的拉伸性能做了初步的研究，得到一些有意义的现象。

Experiment Study on Stress-Induced Transformation of NiTi Single Crystal Shape Memory Alloy

In single crystal shape memory alloy sampling, as there is no bind among crystal grains, its martensite boundary section moves easier than that of polycrystal. Study on its deformation characteristic with experiments is of significance to the establishment of a new theoretical pattern, thus it is important to analyze its experiments. The deformation process of NiTi single crystal shape memory alloy (SMA) was monitored with high sensitive CCD system and the pseudo-elasticity is showed under tension. The orientation of NiTi single crystal sampling under tension was obtained with X-ray diffraction technique. The deformation fields of the stress-induced martensitic transformation of NiTi single crystal SMA were obtained by using high sensitivity Moire interference technique. The infrared camera with high sensitivity was used to keep record of the temperature change of NiTi single crystal in the process of transformation. The initial research on the property of NiTi single crystal under tension in a low temperature has brought about some important phenomena.