7085铝合金的热处理工艺

Heat treatment processes of 7085 aluminum alloy

采用金相显微镜、扫描电镜、电子万能试验机等分析手段对在实验室熔铸的7085铝合金的铸态组织、均匀化退火组织、固溶处理后的组织、固溶时效后的力学性能及断口形貌进行了检测分析。结果表明,采取430℃×12 h+475℃×24 h的双级均匀化退火处理能够完全消除枝晶偏析,Zn原子完全溶解到基体中;在470℃固溶处理时,除少部分粗大第二相外,大部分第二相均回溶到基体中,固溶效果最好; 470℃×120 min固溶+120℃×24 h时效处理后合金的力学性能最佳,屈服强度、抗拉强度、伸长率分别为541 MPa、592 MPa、13. 85%,断口形貌为以穿晶断裂为主的混合型断裂。

The microstructure of as-cast,homogenization annealing and solution treatment of 7085 aluminum alloy prepared in laboratory,the mechanical properties and fracture morphology of the alloy after solution and aging were analyzed by means of metallographic microscope,scanning electron microscope and electronic universal testing machine. The results show that the two-stage homogenization heat treatment process of 430 ℃× 12 h + 475 ℃× 24 h can completely eliminate the dendritic segregation and Zn atoms can be completely dissolved into the matrix. Except for a few coarse second phases,the most second phase is redissolved into the matrix when solution temperature is 470 ℃,and the best solution effect can be obtained. After solution treated at 470 ℃ for 120 min and aged at 120 ℃ for 24 h,the mechanical properties is the best with a yield strength of 541 MPa,a tensile strength of 592 MPa,a productivity of 13. 85% and a fracture morphology of mixed fracture dominated by transgranular fracture.