离心铸造自生初晶Si、Mg_2Si颗粒增强Al基复合材料铸件工艺研究  

Technical Study of In-Situ Primary Si and Mg_2Si Particles Reinforced Al Based Composite Tubes in Centrifugal Casting

作　　者：翟彦博[1] 刘昌明[1] 

机构地区：[1]重庆大学材料科学与工程学院,重庆400030

出　　处：《铸造》2009年第4期344-348,共5页Foundry

基　　金：重庆市自然科学基金资助项目(CSTC;2008BB4177)

摘　　要：采用不同的离心铸造工艺参数制备了自生初晶Si与Mg2Si颗粒增强Al基复合材料筒状铸件,铸件的内层富含增强颗粒,而外层没有增强颗粒。在铸件切削加工过程中发现,采用高温浇注无冷却水喷淋、低过热浇注无冷却水喷淋,以及高温浇注冷却水喷淋工艺参数得到的铸件,其内部存在明显的缩孔缺陷,而采用低过热浇注冷却水喷淋工艺参数制备的筒状铸件,铸件内部没有发现缩孔现象。对缩孔的形成过程分析发现,内层偏移的大量初晶Si、Mg2Si颗粒与铸型的冷却作用导致了筒状铸件的内壁和外壁同时向铸件心部凝固的对向凝固特征,这种对向凝固使得铸件的内部没有足够的液体进行补缩,最终形成缩孔。In-situ primary Si and Mg2Si particles reinforced AI based composite tubes were fabricated by centrifugal casting with different technological parameters. There were a large number of primary particles in the inner layers of tubes, but no particles in the outer layers. During turning of the tubes, shrinkage was found in the interior of tubes fabricated by high temperature pouring without cooling water sprinkling, low superheat pouring without cooling water sprinkling and high temperature pouring with cooling water sprinkling, while no shrinkage in the interior of tubes by low superheat pouring with cooling water sprinkling. The analysis of shrinkage formation process reveals that the large number of primary Si and Mg2Si particles off-set in the inner layer and mould cooling effect result in the opposite solidifying of inwall and ectotheca at the same time, and this opposite solidifying leads to the formation of shrinkage in the interior of tubes.

关 键 词：离心铸造 自生复合材料 初晶SI MG2SI 缩孔 

分 类 号：TB331[一般工业技术—材料科学与工程] TG249.4[金属学及工艺—铸造]