压铸稀土镁合金高周疲劳试验研究

Experimental Investigation on High Cycle Fatigue Behavior of Rare Earth Die Cast Magnesium Alloys Containing Rare Earth

采用升降法对AZ91D、AZ91D+1%Ce和AZ91D+2%Ce压铸镁合金室温高周疲劳行为进行了试验研究。结果表明:适量稀土Ce的添加能够使压铸镁合金AZ91D的室温拉伸性能和疲劳强度得到提高;利用升降法计算出3种成分合金在应力比R=0.1、循环基数为107下的条件疲劳极限分别为96.7 MPa1、16.3 MPa和105.5 MPa,相当于其抗拉强度的46%左右;合金的疲劳断口呈现出准解理与韧窝断裂的混合特征。

High cycle fatigue behavior of die cast magnesium alloys AZ91D, AZ91D＋ 1% Ce and AZ91D ＋ 2 %Ce at room temperature were investigated using up-and-down method. Results showed that tensile and fatigue strengths of AZ91D alloy at room temperature are improved with addition of proper amount of cerium. Fatigue strengths of the three die cast magnesium alloys are 96.7 MPa, 116.3 MPa and 105.5 MPa respectively under stress ratio R = 0. 1 and cycles N = 107 conditions using up-and-down method calculation. The fatigue strengths of the alloys are about 46% of their tensile strengths. The fatigue fracture of test alloys has mixed-rupture characteristics of quasicleavage and dimples.