一、前言低温金相技术可用在低于室温条件下直接观察金相组织的连续变化。这一技术对于研究材料在低温下的马氏体相变,尤其对具有热弹性马氏体形状记忆合金的相变有着重要的意义。如形状记忆合金的M_s点,其定义为产生第一片马氏体组织时的温度,然而目前在国内对此类合金的M_s(包括M_f、A_s和A_f点)的测定均采用低温电阻和低温X射线衍射等方法。上述方法都需待合金内马氏体相转变到一定程度后方能由检测仪有关物理参数的变化反映出来,所以测得的相变温度都不可避免地有较大的误差。迄今,较为精确的方法是利用低温金相显微镜 I. Introduction Low-temperature metallurgical techniques can be used to directly observe the continuous changes of microstructure below room temperature. This technique is of great importance for the study of martensitic transformation at low temperatures of materials, especially for the transformation with thermoelastic martensitic shape memory alloys. Such as shape memory alloy M_s point, which is defined as the first generation of martensite temperature, but at present in the country for such alloys M_s (including M_f, A_s and A_f points) were measured using low temperature resistance and low temperature X-ray diffraction and other methods. All of the above methods need to be alloy martensite phase transition to a certain extent after the detector can be reflected by changes in the physical parameters, so the measured phase transition temperature will inevitably have greater errors. To date, a more accurate method is the use of low temperature metallurgical microscopy