复合添加Zr、Cr、Pr对超高强铝合金腐蚀和断裂行为的影响  

Effects of composite additions of Zr,Cr,Pr on corrosion and fracture behavior of super-high strength aluminum alloys

作　　者：叶登峰[1] 陈康华[1] 方华婵[1] 

机构地区：[1]中南大学粉末冶金国家重点实验室,长沙410083

出　　处：《粉末冶金材料科学与工程》2011年第3期379-385,共7页Materials Science and Engineering of Powder Metallurgy

基　　金：国家重点基础研究发展规划(973计划)资助项目(2005CB623704);国家自然科学基金委员会创新研究群体科学基金资助项目(50721003);国家科技支撑计划(2007BAE38B06)

摘　　要：采用铸锭冶金法制备Al-Zn-Mg-Cu-Zr合金和Al-Zn-Mg-Cu-Zr-Cr-Pr合金。通过金相和扫描电子显微分析以及拉伸性能、极化曲线、晶间腐蚀、剥落腐蚀与应力腐蚀等性能测试,研究复合添加Zr、Cr和Pr对Al-Zn-Mg-Cu合金腐蚀和断裂行为的影响。结果表明,复合添加Zr、Cr和Pr可显著抑制Al-Zn-Mg-Cu合金的再结晶和晶粒长大,从而提高该合金的抗腐蚀能力和力学性能。与单独添加Zr的Al-Zn-Mg-Cu合金相比,复合添加Zr、Cr、Pr的相同合金的断裂韧性KIC从20.22 MPa.m1/2提高到26.83 MPa.m1/2,应力腐蚀开裂界限应力强度因子KISCC由9.8 MPa.m1/2提高到17.6 MPa.m1/2,抗拉强度、屈服强度及伸长率均有所提高。研究还发现,再结晶晶粒的晶界为腐蚀和断裂的优先选择路径,抑制再结晶和晶粒长大至关重要。Al-Zn-Mg-Cu-Zr and Al-Zn-Mg-Cu-Zr-Cr-Pr super-high strength aluminum alloys have been fabricated by ingot metallurgy method.The effects of composite additions of Zr,Cr and Pr on corrosion and fracture behavior of Al-Zn-Mg-Cu alloys were investigated by optical microscopy,scanning electron microscopy,tensile test,polarization curve measurement,intergranular corrosion,exfoliation corrosion and stress corrosion cracking test.The results show that the composite additions of Zr,Cr and Pr on Al-Zn-Mg-Cu alloys can effectively inhibit the recrystallization and retard the grain growth,which enhances the resistance to intergranular corrosion,exfoliation corrosion and stress corrosion,increasing the tensile properties.Compared with Al-Zn-Mg-Cu alloy with only Zr addition,the Al-Zn-Mg-Cu alloy with composite additions of Zr,Cr and Pr remarkably increases its fracture toughness（KIC） from 20.22 MPa？m1/2 to 26.83 MPa？m1/2,enhances the resistance to stress corrosion cracking（KISCC） from 9.8 MPa？m1/2 to 17.6 MPa？m1/2 and mildly improves the strength and ductility.The results also show that the priority selection of corrosion and fracture behavior is the boundary of recrystallized grain,and it is important to inhibit the recrystallization and retard the growth of the grain.

关 键 词：AL-ZN-MG-CU合金 锆 铬 镨 腐蚀 断裂行为 

分 类 号：TG146.4[一般工业技术—材料科学与工程]