【摘要】 分别在室温大气、室温真空及低温真空几种环境条件下 ,对 1Cr18Ni9Ti钢进行对称载荷拉 -压疲劳试验 ,利用TEM观察疲劳断口附近的显微组织 ,研究了环境因素对疲劳性能的影响 ,并对影响的原因进行了分析和讨论 .研究表明 :1Cr18Ni9Ti钢在低温真空条件下疲劳性能显著提高 ;疲劳断口附近出现大量板条马氏体 ;真空与低温显著提高 1Cr18Ni9Ti钢疲劳性能的原因与真空对裂纹表面的净化效应 ,以及低温促进疲劳裂纹前沿形成板条马氏体有关更多还原

【Abstract】 Fatigue tests for the 1Cr18Ni9Ti steel were performed under the conditions of the room temperature atmosphere, the room temperature vacuum(300 K,10^-4Pa), and the low temperatures vacuum (150,100,（77 K;）10^-4Pa), respectively. Microstructures nearby the fatigue fractures of specimens were analyzed by TEM. The effect of environment on fatigue properties was studied. Results showed that the fatigue properties of 1Cr18Ni9Ti steel were remarkably improved under the conditions of vacuum and low temperatures, and there were many lath martensites nearby the fatigue fractures. The reasons for improving the fatigue properties of 1Cr18Ni9Ti steel caused by vacuum and low temperature were attributed to the cleaning-up effect of vacuum on crack surfaces and the formation of lath martensite induced by low temperature.更多还原