时效温度对轧制态7075铝合金组织及性能的影响

Effects of aging temperature on microstructure and mechanical properties of as-rolled 7075 aluminum alloy

对轧制态7075铝合金采用固溶和时效处理,观察并研究了显微组织、扫描断口。研究发现:不同时效温度下,轧制态7075铝合金晶内和晶界处不同程度析出第二相组织η相,基体晶粒大小有较大差异。其中时效温度为200℃时,晶内和晶界均匀弥散分布着大量第二相,基体晶粒细化;时效温度为220℃时,弥散分布在晶内和晶界的第二相明显减少,并且基体晶粒粗化。时效温度为200℃时,断口韧窝最大最深,表现出典型的韧性断裂。

The experiments of solution and aging were carried out on as-rolled 7075 aluminum alloy , and their microstructure and fracture morphology were observed and analyzed .The results show that when aged at different temperatures , the second phases precipitate in grains and grain boundaries of the 7075 aluminum alloy in various degrees and the grain size is much different .When aged at 200 ℃, the microstructure is fine and many dispersed second phases precipitate in grains and grain boundaries .However , when aged at 220 ℃, the precipitation of the second phases decrease dramatically , the microstructure is coarsened .Meanwhile , when aged at 200℃, the dimension of depth and width of the dimples were almost the greatest , showed a typical ductile fracture .