时效处理对7449铝合金组织和性能的影响  

Effect of aging treatment on microstructure and properties of 7449 aluminum alloy

作　　者：王凤春[1] 李志辉[2] 刘英[2] 李锡武[2] 张永安[2] 

机构地区：[1]东北轻合金有限责任公司,黑龙江哈尔滨150060 [2]北京有色金属研究总院有色金属材料制备加工国家重点实验室,北京100088

出　　处：《金属热处理》2013年第5期92-95,共4页Heat Treatment of Metals

基　　金：国家重点基础研究发展计划课题(2012CB619504);国际科技合作项目(2010DFB50340);国家自然科学基金项目(50904010)

摘　　要：通过电导率、力学性能测试和高分辨率电子显微镜分析,研究了时效处理对7449铝合金组织和性能的影响。研究结果表明,经120℃×24 h峰时效处理后,合金中主要强化相为与基体半共格的η'相和共格的GP区,合金可以获得高的强度性能,抗拉强度、屈服强度和伸长率分别达到671 MPa、621 MPa和13.4%,但电导率偏低,为31.1%IACS。采用双级时效处理,可使合金在保持较高强度的同时获得高的电导率;随第二级时效时间的延长,电导率呈增大趋势,而硬度和强度性能均先增大后减小。合金经115℃×6 h+150℃×18 h时效后可以获得强度性能和电导率的良好匹配,抗拉强度、屈服强度、伸长率和电导率值分别达到656 MPa、630 MPa、12.4%、36.0%IACS,T-L向断裂韧性为28.1 MPa·m1/2;合金中主要的强化相为与基体半共格的η'相和非共格的η相。The effect of aging treatment on microstructure and properties of 7449 aluminum alloy have been studied by measurement of electrical conductivity, mechanical properties and HREM （High Resolution Electron Microscopy） analysis. The results indicate that the main strengthening phase is GP zones, which is coherent with matrix, and semi-coherent η′ phase in the alloy after peak aging treatment at 120 ℃ for 20 h. The alloy exhibits high strength performances, which tensile strength, yield strength and elongation reach 671 MPa, 621 MPa and 13.4% respectively, but the low electrical conductivity is 31.1% IACS. The alloy can obtain high electrical conductivity and maintain high strength after two-stage aging treatment. With increasing secondary aging time, conductivity exhibits the increase tendency, while hardness and strength show the increase trend at first, then decrease. The alloy gains a good match of strength performances and conductivity after aging treatment for 115 ℃ ×6 h ＋ 150 ℃ × 18 h. Tensile strength, yield strength, elongation and conductivity reach 656 MPa, 630 MPa, 12.4% and 35.9% IACS, respectively. Fracture toughness in T-L direction is 28.1 MPa · m1/2. The major strengthening phase is semi- coherent η′ phase and incoherent η phase.

关 键 词：7449铝合金 时效 性能 组织 

分 类 号：TG146.2[一般工业技术—材料科学与工程]