熔体温度对真空差压铸造A357合金组织及性能的影响

Effects of Melt Temperature on Microstructures and Mechanical Properties of A357 Alloy Fabricated by Vacuum Counter-Pressure Casting with Grade-Pressurizing Solidification

研究了不同熔体温度对真空差压铸造分级加压凝固A357合金的相对致密度、微观组织及力学性能的影响。结果表明,熔体温度显著影响真空差压铸造分级加压凝固A357合金的补缩效果、微观组织及力学性能。在熔体温度为590℃时进行分级加压凝固A357合金可以获得高的相对致密度,此时有利于形成较强的补缩流碎断初生相使补缩通道畅通,提高致密度,碎断的初生树枝晶将作为新晶核,形成等轴晶,细化了组织,且获得了最佳的综合力学性能。

Effects of melt temperature on microstructures and mechanical properties of A357 alloy fabricated by vacuum counter-pressure casting with grade-pressurizing solidification were investigated. The results show that the melt temperature affects greatly relative density, microstructure and mechanical properties of A357 alloy in vacuum counter-pressure casting with grade-pressurization solidification. The higher relative density can be obtained by increasing solidification pressure at 590℃, which is beneficial to the smooth channel due to the intense feeding flow formed crashing and breaking the primary to improve the relative density, and broken primary dendrite can be acted as new nuclei to transform the dendrite into equiaxed and refine grain size, so the desirable comprehensive mechanical properties are presented.