微量Yb对Al-Zn-Mg-Cu-Zr超高强铝合金的强韧化作用  

Effect of addition of Yb on strength and toughness of Al-Zn-Mg-Cu-Zr high-strength aluminum alloy

作　　者：陈康华[1] 方华婵[1] 齐雄伟[1] 张茁[1] 

机构地区：[1]中南大学粉末冶金国家重点实验室,湖南长沙410083

出　　处：《中南大学学报（自然科学版）》2008年第4期712-717,共6页Journal of Central South University:Science and Technology

基　　金：国家重点基础研究发展规划资助项目(2005CB623704);国家自然基金委创新研究群体科学基金资助项目(50721003);教育部国防基金和新世纪优秀人才支持计划资助项目(NCET-04-0752);国家自然科学基金资助项目(50471057)

摘　　要：通过拉伸性能和断裂韧性测试、扫描电镜断口分析、金相和透射电镜观察,研究添加微量Yb对Al-Zn-Mg-Cu-Zr超高强铝合金(7A60合金)的显微组织和力学性能的影响;根据合金的显微组织特征,分析添加微量Yb对合金强韧化的作用机理。研究结果表明:在7A60合金中添加0.3%Yb后,形成的含Yb共格弥散相,基体保持形变回复组织,基体晶内未形成明显的亚晶组织,抑制了基体再结晶;与7A60合金相比,添加0.3%Yb的合金拉伸断裂时沿晶界和亚晶界分布的二次裂纹明显减少,沿晶界断裂抗力提高;抗拉强度σb从710MPa提高至747MPa,屈服强度σ0.2从684MPa提高至726MPa,断裂韧性KIC从21.6MN/m3/2提高至29.3MN/m3/2。Effect of addition of Yb on the microstructure and mechanical properties of Al-Zn-Mg-Cu-Zr high-strength aluminum alloy was investigated by measuring tensile properties and fracture toughness, optical and SEM/TEM microscopy. The mechanisms of strengthening and toughening by addition of Yb were analyzed. The results show that when Yb is added to 7A60 alloy, Yb-containing dispersoids can be produced retaining the deformation-recovery Al matrix without obvious sub-grain boundary in the alloy and inhibiting Al matrix recrystallization. By the addition of 0.3% Yb to 7A60 alloy, the intergranular fracture and the second intergranular cracks decrease markedly, and ab increases from 710 MPa to 747 MPa, σ0.2 increases from 684 MPa to 726 MPa, and Kic increases from 21.6 MN/m^3/2 to 29.3 MN/m^3/2, respectively.

关 键 词：高强铝合金 YB 强韧化 再结晶 

分 类 号：TG249.9[金属学及工艺—铸造]