压铸态Mg-7Al-0.5Y合金的低周疲劳行为

研究了压铸态Mg-7Al-0.5Y合金在全反向总应变模式控制下的低周疲劳行为。结果表明,在所采用的不同外加总应变幅下,压铸态Mg-7Al-0.5Y合金均可呈现循环应变硬化,且在0.9%的外加总应变幅下,合金在疲劳变形期间发生了动态应变时效;合金的弹性应变幅、塑性应变幅与断裂时的载荷反向周次之间的关系可分别由Basquin和Coffin-Manson描述。断口形貌的扫描电子显微分析揭示,低周疲劳加载条件下,对于压铸态Mg-7Al-0.5Y合金而言,疲劳裂纹以穿晶方式萌生于疲劳试样表面,并以穿晶方式扩展。

Low-cycle Fatigue Behavior of Die Cast Mg-7Al-0.5Y Magnesium Alloy

The low-cycle fatigue behavior of the die cast Mg-7Al-0.5Y magnesium alloy has been investigated in case of full reversed total strain control mode.The experimental results reveal that die cast Mg-7Al-0.5Y magnesium alloy exhibits the cyclic strain hardening with various total strain amplitudes,in which the dynamic strain aging phenomena can be observed during low-cycle fatigue deformation with the total strain amplitudes of 0.9%.For the die cast Mg-7Al-0.5Y magnesium alloy,the relations between the elastic strain amplitude,plastic strain amplitude and reversals to failure can be described by the Basquin and the Coffin-Manson equation,respectively.The SEM analysis of the fracture morphology shows that the fatigue crack is created at the surface of the specimens and propagated in a transgranular mode in case of low-cycle loading.