采用应变疲劳过程中对试样进行中途回火的方法，研究了回火对疲劳损伤的恢复作用。实验结果发现，中途回火可使疲劳寿命延长。应变量越大，回火的作用越显著；循环寿命分数增加，回火的作用减少。ＴＥＭ观察表明，中途回火使位错密度及位错排列发生变化，从而使疲劳损伤在不同程度上恢复。疲劳断口ＳＥＭ观察发现，中途回火后，应变疲劳断口上的韧性断裂特征比未回火试样明显，说明中途回火使疲劳断裂机制发生了变化 The method of tempering the specimen in the course of strain fatigue was used to study the recovery effect of tempering on the fatigue damage. The experimental results show that half-way tempering fatigue life can be extended. The greater the amount of strain, the more significant the effect of tempering; the increase of the life cycle fraction and the reduction of the tempering effect. TEM observation shows that the mid-tempering changes the dislocation density and the dislocation arrangement, so that the fatigue damage can be recovered to some extent. Fatigue fracture SEM observation found that after the mid-tempering, the ductile fracture fracture toughness fracture characteristics than the non-tempering of the sample significantly, indicating that the intermediate tempering fatigue fracture mechanism has changed