一、前言 宇航工业、超导技术、高能物理、受控热核反应和电子技术等尖端科学技术的发展,要求冶金工作者研制出能在低温下使用的优质结构材料。对于这些材料,低温力学性能的测试是必不可少的。因此需要建立材料的低温试验装置及试验方法。以液氢为低温介质的试验装置,易爆不安全,需要采取一系列安全防爆措施,所以目前的试验装置多采用液氦作低温介质。由于液氦制取困 I. Introduction The development of cutting-edge science and technology, such as aerospace industry, superconducting technology, high-energy physics, controlled thermonuclear reaction and electronic technology, requires metallurgical workers to develop high-quality structural materials that can be used at low temperatures. For these materials, low temperature mechanical properties of the test is essential. Therefore, the need to establish the material of low-temperature test equipment and test methods. Liquid hydrogen as the medium of low temperature test device, explosive insecurity, the need to take a series of safety precautions, so the current test device to use liquid helium as a low temperature medium. Because of liquid helium trapped