强化固溶对7050铝合金组织与性能的影响

Effect of strengthening-solid-solution on microstructure and properties of 7050 aluminum alloy

采用室温拉伸、电导率测试、金相及扫描电镜观察、晶间腐蚀分析手段,研究强化固溶对7050铝合金强度、电导率、微观组织和晶间腐蚀性能的影响。结果表明,经强化固溶处理后合金强度、电导率和腐蚀性能均超过单级固溶;提高强化固溶温度可促使粗大第二相大量回溶,且合金未出现过烧及晶粒明显长大现象,合金抗拉强度由546 MPa提高到572 MPa,拉伸断裂主要为韧窝断口,断口中粗大第二相粒子数量下降,使穿晶韧窝型断裂部分转向沿晶断裂。合金电导率稍许降低,抗晶间腐蚀性能显著提高。

The strength, electronic conductivity, microstructure and intergranular corrosion resistance of 7050 aluminum alloy treated with strengthening solid solution treatment were studied by room temperature tensile, electronic conductivity test, optical microscopy, SEM and intergranular corrosion experiments. The results show that compared with single-stage solution treatment, the strengthening solid solution treatment improves its strength, electronic conductivity and corrosion resistance. When the strengthening solid solution temperature raises, large amounts of the coarse second phases dissolve without over-burning and obvious grains＇ growth. Its strength increases from 546 MPa to 570 MPa. The fracture mode of rupture is mainly dimple fracture, and the coarse second phases decrease which leads to some part of transcrystalline dimple fracture transiting to intergranular one. The strengthening solid solution slightly decreases its conductivity and greatly improves its intergranular corrosion resistance.