离心真空吸铸成形叶轮件凝固组织与性能研究

Solidification Microstructure and Properties of Aluminum Alloy Impeller Produced by Centrifugal Counter-Gravity Casting

采用真空吸铸及离心真空吸铸工艺生产了铝合金叶轮铸件,并研究了不同工艺对铸件凝固组织与力学性能的影响。结果表明,与真空吸铸相比,离心真空吸铸有利于提高金属液的充型流动和凝固补缩能力,获得完整的铸件;真空吸铸时施加离心旋转,可在铸件凝固期间促进枝晶的断裂和游离,抑制枝晶的生长,减小二次枝晶间距并使枝晶尺寸具有较好的均匀性,所获得铸件具有良好的力学性能。

The solidification microstructure and properties of aluminum alloy impeller produced by centrifugal counter-gravity casting were investigated. For comparison, vacuum suction casting was also used. Applying centrifugal force during centrifugal counter-gravity casting is found to have a significant effect on α-Al dendrites, which are fragmented into smaller spherical particles. Furthermore, applying centrifugal force at the early stage of centrifugal counter-gravity casting also improves the filling and feeding capacity during solidification and thereby reduces the formation of defects such as shrinkage porosity and shrinkage cavity. This investigation demonstrates that centrifugal counter-gravity casting is very promising to produce high quality complex thin-walled castings.