摘要
采用扫描电镜原位拉伸观察了电解低钛A356合金铸态下裂纹萌生与扩展特征。结果表明:铸态A356合金裂纹优先萌生于二次枝晶臂间薄弱的共晶体区、大块的共晶硅相处;裂纹的扩展主要是微裂纹易沿着共晶体与基体界面扩展,合金组织中的共晶硅相对裂纹的扩展有一定的阻碍作用,当裂纹与共晶硅颗粒相遇时,扩展方向发生偏离而转向裂纹尖端前沿处有共晶体区开裂、共晶硅相发生断裂、或与基体界面发生分离的更薄弱区。
The fracture mechanism of A356 alloys as-cast was investigated. The crack initiation and propagation process were examined by in-situ tensile test using scanning electron microscope. The results show that crack initiates first in the lamellar eutectic area and block eutectic silicon phases. Crack propagates along the matrix/ silicon particle interface. The eutectic Si particles can block the propagation of crack. The crack paths deflect to the weaker area when encountering with Si particles.
出处
《热加工工艺》
CSCD
北大核心
2010年第6期36-38,共3页
Hot Working Technology
基金
河南省国际科技合作项目(084300510006)
河南科技大学博士科研基金资助项目(2008bs025)
关键词
A356合金
原位拉伸
裂纹萌生
裂纹扩展
A356 alloys
in-situ tensile test
crack initiation
crack propagation
