变质和热处理对高强度铸造Al-Cu-Si-Mn合金组织和性能的影响

通过变质处理和热处理实验,研究了不同的Ti变质加入量和固溶时效处理对高强度铸造Al-Cu-Si-Mn合金组织和性能的影响.结果表明,试验材料的铸态组织为粗大的α(Al)固溶体和其晶界分布的θ(Al2Cu)及T(Al12CuMn2)相,加入0.15%～0.2%Ti变质处理可以细化试验材料的铸态组织,变质处理后进行固溶和时效处理,组织由α(Al)固溶体和其晶内弥散分布的二次T相组成,晶界处残留有未完全固溶的T(Al12CuMn2)相,组织中出现α(Al)晶界无析出区.Ti变质处理高强度Al-Cu-Si-Mn合金组织对壁厚效应的敏感性不明显.

Effects of modification and heat treatment on microstructure and properties of Al-Cu-Si-Mn cast aluminum alloy

The effects of different titanium modifier addition and solution and aging on microstructure and mechanical properties of Al-Cu-Si-Mg cast alloy were studied by modification and heat treatment test.The results show that the as-cast microstructure of test materials is made of coarse α(Al) solid solution phase and θ(Al2Cu) and T(Al12CuMn2)phase which distribute in the bound of the grain.When Ti addition is 0.15~0.2wt%,the microstructure of test materials can be refined.After solution and aging heat treatment,the microstructure of test materials is made of α(Al) phase and a lot of dispersed secondary T(Al12CuMn2)phase which distribute in the α(Al) phase and retained T(Al12CuMn2)phase in the bound of grain and the precipitate-free zones surrounding the α(Al)phase was appeared.The microstructure is not sensitive to the thickness effect of high strength Al-Cu-Si-Mn casting alloy.