摘要
压铸AZ91D镁合金中添加稀土Nd后,生成了新的稀土化合物Al11Nd3相,合金显微组织得到细化,力学性能得到提高,但是当Nd的添加量达到1.5%时,合金的力学性能又有所下降。AZ91D+xNd合金拉伸断口具有准解理、撕裂棱及韧窝等韧性特征,但其断裂方式仍属于脆性断裂。含Nd的AZ91D合金疲劳裂纹萌生于试样的表面或亚表面下的孔隙或夹杂处,疲劳裂纹扩展区为平面状断面,含1.0%Nd合金的疲劳辉纹最为清晰,疲劳断口主要表现为脆性与韧性的混合断裂方式,局部存在准解理台阶与河流花样以及穿晶型和沿晶型二次裂纹。
The new rare earth compound AlllNd3 phases are formed, the microstructure refined and mechanical properties improved with different Nd additions in die cast AZ91D magnesium alloys. The mechanical properties of the alloy with 1.5% Nd addition decreased. The tensile fracture surfaces of AZ91D＋xNd alloys possess the toughness fracture features with quasi-cleavage, lacerated ridge and dimple and brittleness fracture mode. The fatigue crack of AZ91D alloys containing Nd initiate at the hole and inclusions under surface and subsurface. The fatigue crack propagation region is composed of some small facets. The most clear fatigue striations appear at the alloy of containing 1.0%Nd. The fatigue fracture surface shows the quasi-cleavage and dimple fracture. The quasi-cleavage step, river Shape, trans-granular and along-granular cracks exist in the local fracture surface.
出处
《铸造》
EI
CAS
CSCD
北大核心
2007年第1期41-45,共5页
Foundry
基金
"十五"国家科技攻关项目(2001BA311A05-2)
吉林省教育厅科技计划项目(2005-025)
关键词
压铸镁合金
ND
拉伸断裂
疲劳断裂
die cast magnesium alloy
Nd
tensile fracture
fatigue fracture
