对新型高氮低镍03Cr16Mn14Mo2N奥氏体不锈钢进行了不同上限温度下的热疲劳试验，通过光学显微镜观察了热疲劳裂纹的萌生及扩展，研究了其热疲劳行为.结果表明：热疲劳裂纹的孕育期随上限温度的升高而缩短，其扩展速率随着循环次数的增加呈先增大后减小的变化趋势；随着上限温度的升高，试验钢V型缺口处的裂纹扩展至0．5 mm时所需的热疲劳循环次数显著降低；热疲劳裂纹在 V 型缺口处优先萌生，随着热循环次数的增加，晶界和孪晶界也成为裂纹源，裂纹主要沿晶界扩展.
The thermal fatigue tests at different maximum cycle temperatures were carried out on a new-type high-nitrogen-low-nickel austenitic stainless steel 03Cr16Mn14Mo2N.Then the initiation and propagation of the thermal fatigue cracks were observed by optical microscope and the thermal fatigue behavior of the steel was also studied.The results show that the incubation period of the thermal fatigue crack was shortened with the increase of the maximum cycle temperature,and the growth rate first increased then decreased with the increase of cycling number.With the increase of the maximum temperature,the required thermal fatigue cycling number for which the crack at the V-shape notch of the tested steel propagated to the length of 0.5 mm was significantly reduced.The thermal fatigue cracks preferred to initiate at the V-shape notch,then with the increase of cycle number,the grain boundary and twin boundary became the source of crack initiation.The cracks propagated mainly along the grain boundary.
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