多级时效对7075铝合金组织及性能影响

Effect of Multi-stage Aging on Microstructure and Properties of 7075 Aluminum Alloy

采用金相显微镜、冲击试验机、扫描电镜(SEM)及电化学腐蚀仪等试验设备研究了不同时效工艺处理下轧制态7075铝合金的显微组织、断口形貌以及耐腐蚀性。结果表明:在不同时效工艺条件下,7075铝合金的组织形貌、断口形貌及耐腐蚀性差异较大。当单级160℃低温时效时,晶粒组织大小均匀性较差,断裂面中的断裂韧窝较少、较浅且耐腐蚀性较低;当双级200℃中温时效时,晶粒组织大小均匀性较好,同时断裂面中的韧窝较多、较深且耐蚀性较高;当三级240℃高温时效时,晶粒发生粗化,同时断裂韧性变差且耐腐蚀性降低。

The microstructure, fracture morphologies and corrosion resistance for rolled 7075 aluminum alloy under different aging conditions were studied by metallographic microscope, impact testing machine, scanning electron microscope （SEM） and electrochemical corrosion instrument etc. The results show that under different aging conditions, the morphologies, the fracture morphologies and the corrosion resistance of 7075 aluminum alloy have great difference. Under the single stage aging of the low temperature of 160℃, the uniformity of grain size is poor, the fracture toughness nest in the fracture surface is less and shallower, and corrosion resistance is low; under the double stages aging of the medium temperature of 200℃, the uniformity of grain size is better, meanwhile, the fracture toughness nest is deeper and more, and corrosion resistance is higher; under the three stages aging of the high temperature of 240℃ the grains get coarsening, meanwhile, fracture toughness and corrosion resistance get lower.