6005A铝合金均匀化热处理后的冷却工艺对其组织和性能的影响

Effect of Cooling Process on Microstucture and Property of 6005A Alloy after Homogenization Heat Treatment

采用DSC、金相显微组织、电导率等测试分析手段,研究了6005A铸锭均匀化热处理后不同的冷却工艺对其组织和性能的影响。结果表明:铸态合金中存在非平衡共晶相,合金成分分布不均匀,组织呈枝晶状;采用合适的均热工艺进行均匀化热处理后,非平衡共晶组织消失,枝晶偏析消除,成分分布均匀,最佳均匀化制度为560℃/8h。而铸锭的电导率随着均匀化热处理后冷却速度的增加逐渐降低。

The influence of different cooling processes on the microstructure and properties of 6005A ingot after homogenization heat treatment was studied by analysis of DSC, metallographic microstructure and conductivity. The results show that there is a non-equi. librium eutectic phase in the as-cast alloy, the composition of the alloy is uneven and the organization is dendritic. After homogeniza. tion heat treatment, the non-equilibrium eutectic structure disappears and the dendritic segregation is eliminated, the distribution of compositionis uniform, the best homogenization system is 560 ℃/ 8h. The conductivity of the ingot gradually decreases with the in. crease of the cooling rate after the homogenization heat treatment, and the precipitates within the grains gradually decrease with the in. crease of the cooling rate.