热处理对喷射沉积Al-27%Si合金显微组织及力学性能的影响

Effects of heat treatments on microstructures and mechanical properties of spray-deposited Al-27%Si alloy

采用喷射沉积和热挤压致密化相结合的方法制备Al-27%Si合金,研究热处理对合金的组织及性能的影响。利用金相显微镜、扫描电镜和MTS-858型疲劳试验机等手段对Al-27%Si合金喷射沉积挤压态和热处理态的显微组织和力学性能进行观察与测试。结果表明:喷射沉积Al-27%Si合金组织细小均匀,初晶Si均匀弥散地分布在连续Al基体中,无针状共晶硅存在;采用合理的热挤压致密化工艺可以显著消除材料中的孔隙,致密度达到99.5%;热处理能够进一步改善材料的组织,但会降低材料的屈服强度。

A kind of novel packaging material, A1-27% alloy, was prepared by a method comprised of spray deposition and subsequent hot extrusion, then, the effects of heat treatments on the microstructures and mechanical properties of the alloy were studied. The microstructures and mechanical properties of hot extruded and heat treated A1-27%Si alloy were investigated with optical microscope, scanning electronic microscope and MTS-858 type fatigue testing machine. The experimental results show that the spray-deposited AI-27%Si alloy after hot extrusion has fine, homogeneous microstructure with no needle-like eutectic Si but small primary Si particles uniformly dispersed in the Al matrix, besides an increase of size to some degree, even the following heat treatments make little difference to it. Appropriate hot extrusion process can eliminate the porosities remarkably, so as to improve the relative density of the alloy to 99.5%. The microstructures of A1-27%Si experience further improvement after certain heat treatments, while the transformations of mechanical properties are opposite.