微量Er和Cr对超高强Al-Zn-Mg-Cu-Zr合金再结晶行为和性能的影响  

Effects of Cr and Er additions on recrystallization and properties of super-high strength Al-Zn-Mg-Cu-Zr alloys

作　　者：方华婵[1] 陈学海[2] 陈康华[1] 

机构地区：[1]中南大学粉末冶金国家重点实验室,长沙410083 [2]中国南车集团株洲电力机车有限公司,株洲412001

出　　处：《粉末冶金材料科学与工程》2015年第5期690-699,共10页Materials Science and Engineering of Powder Metallurgy

基　　金：国家自然科学基金青年基金资助项目(51501228);湖南省自然科学基金资助项目(2015JJ3167);国家重点基础研究发展计划(973计划)资助项目(2010CB731701)

摘　　要：采用铸锭冶金法制备Al-Zn-Mg-Cu-Zr、Al-Zn-Mg-Cu-Er-Cr和Al-Zn-Mg-Cu-Zr-Er-Cr合金。通过金相显微镜、透射电镜的观察,和硬度、强度、腐蚀性能测试,对比Al-Zn-Mg-Cu-Zr、Al-Zn-Mg-Cu-Er-Cr和Al-Zn-MgCu-Zr-Er-Cr合金的再结晶行为和性能。结果表明,Al-Zn-Mg-Cu-Zr合金中添加微量Er、Cr后生成的含Zn、Mg、Cu的(Al,Cr)3(Zr,Er)相细小弥散,与基体共格,可钉扎位错,稳定亚结构,阻碍亚晶长大及晶界的迁移,从而抑制铝合金基体的再结晶,使合金在510℃仍能保持细小的亚晶组织,再结晶起始温度升高至500℃;在保持高的断裂韧性的同时,合金的应力腐蚀和剥落腐蚀抗力提高,应力腐蚀开裂界限应力强度因子KISCC由10.9 MPa/m1/2升高到22.4 MPa/m1/2,剥落腐蚀由EB+升高至EA+。A1-Zn-Mg-Cu-Zr, A1-Zn-Mg-Cu-Er-Cr and A1-Zn-Mg-Cu-Zr-Er-Cr alloys were prepared by cast metallurgy. The recrystallization behavior and perperties of A1-Zn-Mg-Cu-Zr, A1-Zn-Mg-Cu-Er-Cr and A1-Zn-Mg-Cr-Zr-Er-Cr alloys were compared by optical microscopy, transmission electron microscopy, tensile test and corrosion resistance measurement. The results show that the dispersed L12-structured Zn, Mg, Cu, Cr-containing A13（Zr, Er） dispersoids can strongly pin dislocations, stabilize substructures and inhibite the movement of botmdaries. A small subgrain structure is maintained even heated at 510 ~C in A1-Zn-Mg-Cu-Zr-Er-Cr alloy. Hence, the recrystallization temperature of A1-Zn-Mg- Cu-Zr-Er-Cr alloys reaches to 500 ~C. By combined additions of Er and Cr, the critical stress intensity （Kascc） increases from 10.9 MPa/mm to 22.4 MPa/m1/2 and exfoliation corrosion increases from EB＋ to EA＋, with the improved strength, fracture toughness and ductility.

关 键 词：Al—Zn—Mg-Cu合金 铒 再结晶 腐蚀 断裂 

分 类 号：TG146.2[一般工业技术—材料科学与工程]