高温合金材料热机械疲劳实验技术

Techniques for Thermomechanical Fatigue Testing on High Temperature alloys

本文以ＡＩＳＩ３１６Ｌ不锈钢材料为例介绍了高温低周应变控制热机械疲劳（ＴｈｅｒｍｏｍｅｃｈａｎｉｃａｌＦａｔｉｇｕｅ）试验，温度循环和机械应变循环为相同频率，它们间的相位关系分为同相位和反相位两种．温度循环范围选为２５０～５００℃和２５０～６５０℃两种．通过计算机自动控制的实验系统所得到的试验数据，探讨了热机械疲劳应力－应变响应，裂纹萌发和扩展的性质，材料微观损伤分析和温度范围变化对疲劳性能和寿命的影响．对疲劳试验过程中循环回滞曲线的分析，给出了材料硬化阶段和循环稳定阶段的特性．

High temperature low-cycle thermomechanical fatigue (TMF) test for AISI 316L austenitic stainless steel is reported. The test is under total strain control, and with the cylce of temperature inphase or outofphase to the cycle of strain. The temperature intervals used in the test are 250℃-500℃ and 250℃-650℃.Based upon a computerized data acquisition and processing system, the stressstrain response, the crack initiation and propagation characteristic, the microstructure of damage behavior and the influence of temperature interval on fatigue life are obtained. The hysteresis loops exhibited in the fatigue test for the material are also analyzed.