冷却速率对Al-Si-Mg三元合金凝固过程的影响  

Effects of Cooling Rates on the Solidification Process of Al-Mg-Si Alloy

作　　者：何志[1] 张瑞杰[1] 介万奇[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,陕西西安710072

出　　处：《铸造》2005年第2期187-189,共3页Foundry

基　　金：国家重点基础研究发展规划项目(G2000067202 1)。

摘　　要：试验研究了冷却速率对Al 2 06%Si 1 58%Mg三元合金凝固过程的影响。同时通过热力学计算预测了不同冷却条件下Al 2 06%Si 1 58%Mg三元合金的凝固路径和相析出规律。试验及计算结果均表明,改变凝固速率可使Al 2 06%Si 1 58%Mg合金的凝固过程按照不同的路径进行,从而达到控制析出相种类的目的。在低的冷却速率下,相析出规律为:L→L1+FccA1→L1+FccA1+Si→L1+FccA1+Si+Mg2Si,而在较高的冷却速率下,相析出规律为:L→L1+FccA1→L1+FccA1+Mg2Si→L1+FccA1+Si+Mg2Si。The effect of cooling rates on the solidification process of Al-2.06wt% Si-1.58wt% Mg was experimentally investigated. The solidification paths and the phase precipitation sequence were predicted coupled with the thermodynamic calculation. Due to the additional freedoms under the isothermal condition in multi-component alloys, the solute transportation and the solidification paths can be largely influenced by the cooling rates. It was proved through both experiments and calculation that different phase precipitation sequences were followed under different cooling rates. The solidification sequences are L -> L1+Fcc_Al -> L1+Fcc_Al+Si -> L1+Fcc_Al+Si+Mg2Si under low cooling rate and L -> L1+Fcc_Al -> L1+Fcc_Al+Mg2Si -> L1+Fcc_Al+Si+Mg2Si under high cooling rate, respectively.

关 键 词：冷却速率 溶质传输 三元合金 

分 类 号：TG27[金属学及工艺—铸造]