中文摘要：

以新型1900 MPa级超高强度马氏体时效不锈钢为研究对象,通过激光扫描共聚焦显微镜对其超声疲劳试样断口进行观察与分析。结果表明,在超声疲劳试验过程中,所有的试样在表面均产生了烧蚀的痕迹。对于表面起裂的超声疲劳试样,即使在不同的应力幅值下（640-560 MPa）,试样的疲劳寿命均在10^5周次左右,且烧蚀现象更为严重。而对于基体内起裂的试样,烧蚀现象较为轻微,且烧蚀处均在断口两侧几乎对称的位置。经对比分析可知,超声疲劳过程中产生的热效应对表面起裂试样的疲劳寿命有很大的影响,而内部起裂试样的疲劳寿命对超声疲劳热效应不敏感。

英文摘要：

Heat effect on ultrasonic fatigue of a new 1900 MPa grade ultra-high strength maraging stainless steel had been investigated by laser scanning confocal microscope observation. Ultrasonic fatigue test shows that all the samples are retained a burn trace during the whole process of ultrasonic fatigue test. The sample fatigue life is full at the 105 cycles,even with the stress range of 640-560 MPa for the surface fatigue cracking samples and burning is more serious. The burning is more slightly for the matrix inner cracking sample and the burning position is all located symmetrically at both side of fracture. It is known by comparision,that the influence of heat effect resulted from ultrasonic fatigue process on fatigue life of surface cracking sample has a serious role,and the fatigue life of matrix inside cracking sample is no sensitive to heat effect of ultrasonic fatigue.