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一、金属的疲劳断裂金属材料或机械构件在循环负载或交变应力作用下,经过较长时间工作而发生断裂的现象叫做金属的疲劳。它们所承受的应办通常都低于材料的强度极限,有时也低于屈服极限,甚至低于弹性极限。断裂是突然发生的,并且都不产生明显的塑性变形,因此,具有很大的危险性,据统计,在损坏的机器零件中,度劳损坏的比例约占90％左右,因此,人们对于疲劳断口的研究特别重视,至今已有近200年的研究历史了。
First, the metal fatigue fracture Metallic materials or mechanical components in the cyclic load or alternating stress, after a long time working breakage phenomenon called metal fatigue. They should usually bear below the material’s strength limit, sometimes below the yield limit, or even below the elastic limit. Fractures are a sudden, and do not produce significant plastic deformation, therefore, has a great danger, according to statistics, in the damaged machine parts, the proportion of labor-related damage accounts for about 90%, therefore, people are tired The study of fracture has paid special attention. So far, it has been nearly 200 years of research history.