摘要
AZ91D压铸镁合金中加入富Ce稀土后,组织得到明显细化,压铸过程中产生的气孔变小,分布更加均匀,能够减少疲劳裂纹源的产生。AZ91D合金拉伸断口表现为既有解理台阶又存在细小撕裂棱及韧窝的混合断裂特征,加入1%Ce后,合金断口的韧性断裂特征增加,有利于提高合金的室温力学性能。AZ91D合金疲劳裂纹源萌生于合金内部的气孔和夹杂处,疲劳裂纹沿晶界扩展,加入稀土后,疲劳裂纹扩展区有疲劳辉纹出现,疲劳断裂呈现出准解理和韧窝断裂的混合特征。
The microstructure of AZ91D magnesium alloy is refined evidently with addition of rich-cerium rare earth. The gas hole is smaller and distribute even uniformly. The formation probability of fatigue crack initiation is decreased. The tensile fracture surface possess the mixed-rupture characteristics of cleavage step, minute lacerated ridge and tough dimple existence. The toughness fracture features of alloy tensile fracture surface are increased after addition 1%Ce, which is in favor of improving the mechanical properties of alloys at room temperature. The fatigue crack of AZ91D alloy initiates at gas hole and inclusions of alloy inside. The fatigue crack propagates along the grain boundary. The fatigue lines appear in the fatigue crack propagation zones after addition rare earth. The fatigue fracture zone shows the mixed-rupture characteristics of quasi-cleavage and dimple.
出处
《铸造》
EI
CAS
CSCD
北大核心
2006年第2期135-139,共5页
Foundry
基金
"十五"国家科技攻关项目(2001BA311A05-2)
吉林大学"985工程"汽车工程科技创新平台资助。
关键词
AZ91D
压铸镁合金
显微组织
拉伸断口
疲劳断口
AZ91 D
die cast magnesium alloy
microstructure
tensile fracture surface
fatigue fracture surface
