引言 金属材料的疲劳破坏和应力腐蚀破坏绝大部分起源于表面或近表面层,这是由试件或零件的表面具有独特的状况而决定的。所谓表面状况,这里系指各种类似裂纹的缺陷(如表面机械划伤,焊接裂纹,锻铸缺陷,脱碳,合金元素贫化,非金属夹杂物等),以及由冷热加工引起的残余应力(主要是残余拉应力)。由 Introduction The fatigue failure and stress corrosion cracking of metallic materials originate mostly from the surface or near-surface layer, which is determined by the unique condition of the surface of the test piece or part. The so-called surface conditions, here refers to all kinds of cracks similar to the defects (such as mechanical surface scratches, welding cracks, forging defects, decarburization, alloying elements, non-metallic inclusions, etc.), and caused by hot and cold processing of the residual Stress (mainly residual tensile stress). by