固溶降温处理对7A55铝合金组织和性能的影响

Effects of Cooling Treatment Following Solution on Microstructures and Properties of Aluminum Alloy 7A55

采用光学显微镜、扫描电镜和透射电镜及力学性能、电导率测试研究了固溶降温处理对7A55铝合金板材组织和性能的影响。结果表明:固溶降温处理可以改变7A55铝合金板材中晶内和晶界的析出状态,提高合金电导率。从480℃降至440℃以下保温30 min,或转炉降温时都会导致合金强度的大幅度下降。从480℃随炉冷至440℃保温30 min,7A55铝合金板材时效后晶界上的第二相呈不连续分布,合金强度降幅较小,电导率却有较大的升高,可获得较好的综合性能。

The effects of cooling treatment following solution on microstructures and properties of aluminum alloy 7A55 were investigated by optical microscopy （OM）, scanning electron microscopy （ SEM ） and transmission electron microscopy （TEM）, mechanical properties and electrical conductivity testing. It was showed that the precipitates on the grain boundaries were discrete after cooling treatment following solution, and the electrical conductivity was increased,too. Significant drop in hardness and strength of the alloy was observed by furnace-quenching or holding at a temperature below 440 ℃ following solution of 480 ℃/30 min. The optimum treatment was furnacecooling to 440 ℃ and holding for 30 min following solution, which led to discrete precipitates on the grain boundaries and higher electrical conductivity with slight drop in strength.