真空热循环对空间级缩合型硅橡胶拉伸性能的影响

对空间级缩合型硅橡胶KH－X－B进行了真空热循环试验（123－403K，10^-5Pa），测试了热循环前后材料的质损率，拉伸性能，热膨胀性能，讨论了循环过程中的应变滞后效应和附加残余应变以及它们对材料的强化作用，结果表明，材料质损率随循环次数增加而提高后趋于平缓，室温及高温拉伸强度随循环次数的增加是先增强而后下降，循环过程中发生应变滞后现象，且第一次循环后产生附加残余应变，206次循环后残余应变消失，材料强化，400次循环后重新产生残余应变，材料强度下降。

Effect of Thermal Cycling on Tensile Properties of Space Grade Silicon Rubber in Vacuum

The thermal cycling tests on the space grade silicon rubber were carried out in vacuum (123~403K, 10 -5 Pa) The weight loss rates, tensile and thermal expansion properties before and after cycling were measured The thermal strain hysteresis and additional residual strains as well as their hardening effects on the materials were discussed for the first time Results show that the weight loss rate is first increased and then keep unchanging with increasing cycles The tensile strength at room and elevated temperature is first increased and then decreased with increasing cycles The thermal strain hysteresis occurs in the cycling The additional residual strain that is produced in the first cycle disappears after the 206th cycles with the hardening of the materials When it reachs the 400th cycles, the residual strain is reproduced and the strength of the tested materials is decreased