7050铝合金铸锭均匀化热处理

Homogenization heat treatment of 7050 aluminum alloy ingot

试验研究了7050铝合金铸态及不同温度-时间均匀化处理后的组织演变。研究结果表明:铸态组织中存在严重枝晶偏析,400℃均匀化处理过程中,非平衡凝固共晶相向合金基体持续溶解,在465℃均匀化时,平衡η(MgZn2)相、T(Al Zn MgCu)相等大部分共晶相回溶到基体中,晶界明显细化,均匀化效果显著。确定了7050铝合金铸锭最佳均匀化工艺制度为465℃保温24 h。

The microstructure evolution of 7050 aluminum alloy was studied both in as-cast state and after different temperature-time homogenization. The results show that severe dendrite segregation exists in the as-cast structure. In the homogenization process at 400℃,the non-equilibrium solidification eutectic phase continues dissolving in the alloy matrix. At465℃,the equilibrium η( MgZn2) phase,T( AlZnMgCu) phase,and most of the eutectic phase dissolves back into the matrix. The grain boundaries are remarkably refined and the homogenization effect is remarkable. The optimum homogenization scheme of 7050 alloy ingot is at 465℃ holding for 24 h.