金属疲劳断裂,是指金属材料在低于拉伸强度极限的交变应力反复作用下缓慢发生的疲劳裂纹,经逐步扩展后导致突然破坏的断裂。根据交变载荷(应力)振幅的大小,一般可分为应力和应变疲劳,或称高循环和低循环疲劳。 疲劳问题的重要性,不但在于绝大多数工程零件(估计约占90％)的提前破坏属于疲劳断裂,而且因为疲劳裂纹的产生和扩展,往往 Metal fatigue fracture, refers to the metal material under the alternating tensile stress below the tensile strength of the slow fatigue cracks occur, gradually expanded to cause sudden rupture. According to the alternating load (stress) the size of the amplitude can generally be divided into stress and strain fatigue, or high cycle and low cycle fatigue. The problem of fatigue is not only that the premature failure of the vast majority of engineering components (an estimated 90% of the total) is fatigue fracture but also because of the generation and expansion of fatigue cracks,