【摘要】 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。更多还原

【Abstract】 The multi-stage hot deformation simulation of 7055 aluminum alloy was performed on Gleeble-1500D thermal simulator.The characteristics of hot-press structure under different strain rates were analysed by TEM,and the metallographic structure and mechanical properties after hot treatment were observed and tested respectively,the effects of hot deformation strain rate on the microstructure and mechanical properties of 7055 aluminum alloy were investigated.The results of experiments indicate that partial recrystallization takes place in the alloys deformed at a low level strain rate(0.01 s-1),and the subgrain size decreases and the dislocation density increases in the alloy with increasing strain rate.Correspondingly,the subgrain decreases and the recrystallized grain increases after heat treatment.The samples gain a higher mechanical properties with the fractions of recrystallized grain decrease after heat treatment.The sample exhibited highest strength and hardness under the strain rate of 1 s-1.更多还原