Al-5.5Zn-2.5Mg高强铝合金微观组织与疲劳性能  

Microstructure and Fatigue Properties of Al-5.5Zn-2.5Mg High Strength Aluminum Alloy

作　　者：孙现亮[1] 杨尚磊[2] 徐超[2] 丁波[2] 林庆琳[1] 

机构地区：[1]南车青岛四方机车车辆股份有限公司,青岛266111 [2]上海工程技术大学材料工程学院,上海201620

出　　处：《上海工程技术大学学报》2013年第2期137-140,共4页Journal of Shanghai University of Engineering Science

基　　金："十一五"国家关键攻关项目(2009BAG12A04);国家自然科学基金资助项目(51075256);上海市教委科研创新重点资助项目(11ZZ177)

摘　　要：通过光学显微镜(OM)、扫描电镜(SEM)和透射电镜(TEM)等方法观察了Al-5.5Zn-2.5Mg高强铝合金材料的微观组织,并进行了拉伸性能与疲劳性能试验,分析其拉伸断裂和低周疲劳失效行为.结果表明:Al-5.5Zn-2.5Mg高强铝合金的力学性能与低周疲劳性能较好,拉伸强度达到479.4MPa.当应力比R=-1,频率f=20Hz,应变幅εa=0.8%时,低周疲劳寿命为630周,疲劳裂纹萌生于试件表面,且疲劳裂纹扩展区存在明显的疲劳条带.Al-5.5Zn-2.5Mg铝合金η′(MgZn2)析出相虽然在光学组织中呈现均匀弥散分布,但在TEM高倍组织中主要沿晶界析出,强化相粒子的平均直径约20nm,晶界附近无沉淀析出带宽约100nm.The microstructure of Al-5.5Zn-2.5Mg high strength aluminum alloy was observed by OM,SEM and TEM,the tensile and fatigue properties were tested and the tensile fracture and low cycle fatigue failure behavior were analyzed.The results show that the mechanical properties and low cycle fatigue properties of Al-5.5Zn-2.5Mg high strength aluminum alloy are fine.The tensile strength is 479.4 MPa.The low cycle fatigue life is 630 cycles in the condition of R=-1,f=20 Hz,and εa=0.8%.The fatigue crack initiates on the surface of the sample,and the fatigue striation exists in fatigue crack propagation zone.The η′（MgZn2） strengthening phase is evenly precipitated in Al-5.5Zn-2.5Mg aluminum alloy in optical microstructure,and mostly distributed in grain boundary in TEM high magnification microstructure.The diameter of strengthening phase is about 20 nm,the width of none precipitated zone nearby the grain boundary is 100 nm.

关 键 词：高强铝合金 微观组织 疲劳性能 力学性能 

分 类 号：TG146.2[一般工业技术—材料科学与工程]