固溶处理工艺对改良铸造铝硅合金组织和性能的影响

摘要

By aid of solution system with different temperature and time, effect of solution treatment process on the microstructure and mechanical properties of modified aluminium silicon casting alloy(0.35% Mg,7.0% Si,0.2% Ni,2.0% Cu,0.8% RE,0.2% Mn, 0.1% V,balance is Al)was studied. The results show that,at 495℃×5h for solution treatment,modified aluminium silicon casting alloy has the best comprehensive mechanical properties:б=239MPa,HBS=103HBS,β=6.24%;modified aluminium silicon casting alloy at 495℃×5h after solution quench had Si,AlCu,Al6Cu3Ni,AlxCuCe phases containing rich Si,Cu,Ni and RE elements. These phases were helpful to improve the mechanical properties and high temperature performance of alloy. Ductile fracture for alloy after heat treatment is the main way and is accompanied by the quasi cleavage phenomenon. The tensile fracture morphology is mainly dimple fracture characteristics, some of the presence of a small amount of tear ridges.%通过不同温度和时间的固溶制度研究了固溶处理工艺对改良铸造铝硅合金（0.35%Mg，7.0%Si，0.2%Ni，2.0%Cu，0.8%RE，0.2%Mn，0.1%V，其余为铝）组织和性能的影响。实验结果表明，在495℃×5h进行固溶处理时，改良铸造铝硅合金具有最好的综合力学性能：Rm=239MPa，硬度=103HBS，A=6.24%；改良铸造铝硅合金于495℃×5h固溶淬火析出富含Si、Cu、Ni以及RE元素的Si、AlCu、Al6Cu3Ni、AlxCuCe相。这些相的存在，有利于提高合金的力学性能和高温性能。合金经过热处理后以韧性断裂为主要方式并伴有准解理面现象，拉伸断口微观形貌主要表现为韧窝断口特征，有些存在少量撕裂棱。