热处理对挤压变形AM50镁合金疲劳行为的影响

Influence of heat treatment on fatigue behavior of extruded AM50 alloy

采用低周疲劳试验研究了固溶处理和时效处理对挤压变形AM50镁合金在疲劳加载条件下的变形行为和疲劳寿命的影响.结果表明,固溶和时效处理均可改变挤压变形AM50镁合金的循环应力响应行为和循环应力-应变行为,并降低挤压变形AM50镁合金的循环应变硬化指数和循环强度系数;在高的外加总应变幅下,固溶和时效处理可以提高挤压变形AM50镁合金的疲劳寿命,但当外加总应变幅较低时,固溶和时效处理则降低挤压变形AM50镁合金的疲劳寿命;固溶处理将抑制挤压变形AM50镁合金在疲劳变形期间发生动态应变时效.

The influence of heat treatment including solid solution and aging treatments on the deformation behavior and fatigue life of the extruded AM50 magnesium alloy was investigated by means of low-cycle fatigue tests. The results reveal that the solid solution and aging treatments will lead to a change in both cyclic stress response and cyclic stress-stain behavior of the extruded AM50 alloy. The cyclic strain hardening exponent and cyclic strength coefficient will decrease after solid solution and aging treatments. Both solid solution and aging treatments will enhance the fatigue resistance of the extruded AM50 alloy at the high total strain amplitudes, while decrease the fatigue life of the alloy at the lower total strain amplitudes. In addition, it has been noted that the solid solution treatment will restrict the occurrence of dynamic strain aging induced by fatigue deformation for the extruded AM50 alloy .