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采用Gleeble-1500D热模拟试验机对7055铝合金进行了多道次热模拟压缩试验,利用TEM分析合金在不同应变速率条件下热压缩组织特征,观察合金在热处理后的金相组织形貌并进行力学性能测试,研究了热变形应变速率对7055铝合金显微组织和力学性能的影响。实验结果表明:在较低的热变形应变速率(0.01 s-1)条件下合金发生了部分动态再结晶,并且在经随后的热处理后亚晶数量减少,再结晶数量增多。随着应变速率的增大,合金中的亚晶尺寸减小,位错密度增大。热处理后合金的再结晶体积分数越小,合金的力学性能也越高,当热变形应变速率为1 s-1时,合金经热处理后合金再结晶体积分数约为45%,合金呈现最高的强度性能。
The multi-pass thermal simulation of 7055 aluminum alloy was carried out by Gleeble-1500D thermal simulation tester. The microstructure of hot-pressed alloy under different strain rates was analyzed by TEM. The morphology of the alloy after heat treatment was observed and investigated. The mechanical properties of the 7055 aluminum alloy were investigated. The effect of thermal deformation strain rate on the microstructure and mechanical properties of 7055 aluminum alloy was investigated. The experimental results show that the alloy undergoes partial dynamic recrystallization under the condition of low thermal deformation strain rate (0.01 s-1), and the amount of the subgrain decreases and the recrystallization number increases after the subsequent heat treatment. As the strain rate increases, the size of the subgrains in the alloy decreases and the dislocation density increases. The smaller the recrystallization volume fraction is, the higher the mechanical properties of the alloy are. After hot deformation strain rate of 1 s-1, the recrystallization volume fraction of the alloy after heat treatment is about 45%, and the alloy shows the highest strength performance.