铸造共晶铝硅合金中析出相对断裂行为的影响  

Effects of precipitates on the fracture behavior of cast eutectic Al-Si alloys

作　　者：王恩睿[1,2] 惠希东[1] 王建国[1] 谷凤龙[2] 

机构地区：[1]北京科技大学新金属材料国家重点实验室,北京100083 [2]邯郸钢铁集团有限责任公司,邯郸056001

出　　处：《北京科技大学学报》2011年第12期1508-1515,共8页Journal of University of Science and Technology Beijing

基　　金：国家自然科学基金重点资助项目(50871013;51071018)

摘　　要：通过对铸造共晶Al-Si合金断口及析出相的分析研究了拉伸过程中基体内析出相的断裂特点.结果发现:拉伸过程中基体内初、共晶硅以穿晶断裂为主,这与颗粒内部存在的结构缺陷有关;直径小于2.0μm的初晶硅能够抑制二次裂纹的扩展.块状富铁相表现出穿晶断裂特点,鱼骨状富铁相中的微裂纹沿一次枝晶轴向生长.富铜相对裂纹扩展具有强烈地偏折作用;以富铁相为核心析出的富铜相能抑制富铁相中微裂纹的形成.提高合金中Cu含量可以降低富铁相的有害作用,改善合金的力学性能.The fracture characteristics of precipitates in cast eutectic Al-Si alloys were studied during tensile processes by observing the fracture and precipitates.It is shown that the primary/eutectic Si cracks mainly through transcrystalline fracture owing to structural defects.Primary Si with a diameter size less than 2.0μm can block the propagation of secondary cracks.The blocky iron-rich phases crack through transcrystalline fracture,while cracks within the Chinese script iron-rich phases propagate along their primary dendrites.The copper-rich phases deflect the crack propagation and inhibit the nucleation of microcracks within the iron-rich phases.Increasing the Cu content neutralizes the harmful effects of the iron-rich phases to some extent and is of benefit to the mechanical properties.

关 键 词：铝合金 硅合金 共晶 析出相 微裂纹 力学性能 

分 类 号：TG146.21[一般工业技术—材料科学与工程]