摘要
本文用SEM研究了粒度分别为<40μm、40～100μm、100～154μm的挤压A1-3.3Li-1.01Mg-0.06Zr合金的拉伸断口。其共同特征是裂纹均起始于试样内部的夹渣,并以放射剪切特征扩展。颗粒度不同,剪切源的粗细及形式也不同。颗粒度<40μm的合金,剪切源细且呈劈-剪型(aI),表现为穿晶与个别沿晶断裂,沿粉末边界脱开的二次裂纹较多且粗。40～100μm的粉末合金,断口的放射剪切源粗,呈锯齿型(aII),出现穿晶加个别沿晶的层状断裂。沿粉粒界面劈开的二次裂纹较少,并存在一些塑性变形良好的小锥特征。100～154μm粉末合金的断口放射剪切源粗并呈aI型,明显可见沿粉界劈开的二次裂纹为穿晶沿晶混合断裂。
The tensile fracture characteristics of extruded Al-3.3Li-1.01Mg-0.06Zr alloys with the powder sizes of below 40μm, 40-100μm,100-154μm have been studied. The general macroscopic features show that cracks initiate around constituent particles and propagate in the form of radiation-Shear mode. Different powder sizes result in different morphologies of the shear sources. When powder size is below 40μm,cleavage (aI) shear source and transgranular failure with limited intergranular failure are observed. The secondary cracks along powder boundaties are frequently observed, which are extensive and coarse. With powder size of 40-100μm the shear sources are coarse and in the shape of zigzag(aII). Delamination fracture with mixture of transgranular and limited intergranular appeared. The number of the secondary cracks along powder boundaries are less. The appearance of some small cones indicates higher plastic deformation.When powder size is between 100-154μm, shear sources are coarse and show aI mode.Secondary cracks along powder boundaries are obviously examined.The characteristic of mixture fracture with transgranutlar and intergranular failure is demonstrated.
出处
《航空材料学报》
EI
CAS
CSCD
1990年第A09期85-94,共10页
Journal of Aeronautical Materials
