T6I4和T6I6时效处理对7050铝合金疲劳性能的影响  

Influence of T6I4 and T6I6 aging treatments on fatigue properties of 7050 Al alloy

作　　者：陈宇强[1] 宋文炜[1] 潘素平[2] 刘文辉[1,3] CHEN Yuqiang SONG Wenwei PAN Suping LIU Wenhui(College of Electromechanical Engineering, Hunan University of Science and Technology, Xiangtan 411201, China Advanced Research Center, Central South University, Changsha 410083, China Key Lab of High Temperature Wear Resistant Materials Preparation Technology of Hunan Province, Hunan University of Science and Technology, Xiangtan 411201, China)

机构地区：[1]湖南科技大学机电工程学院,湖南湘潭411201 [2]中南大学高等研究中心,湖南长沙410083 [3]湖南科技大学高温耐磨材料及制备技术湖南省国防技术重点实验室,湖南湘潭411201

出　　处：《中南大学学报（自然科学版）》2016年第10期3332-3340,共9页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(51405153;51475162);中南大学实验室建设与管理研究项目(160260001)~~

摘　　要：采用硬度测试、力学拉伸测试、透射电镜分析(TEM)以及疲劳性能测试等方法研究T6I4和T6I6这2种间断时效处理对7050合金力学拉伸性能以及疲劳寿命的影响。研究结果表明:与T6时效相比,T6I6峰时效合金的屈服强度和抗拉强度分别提高5.2 MPa和10.6 MPa,同时伸长率也增大1.9%;T6I4峰时效合金的伸长率增大2.9%,但强度略有下降;经T6I4和T6I6时效处理后,合金晶内具有高密度的η′相而晶界则分布着不连续的η相;在相同疲劳加载条件下,T6I6峰时效态合金的裂纹源数目最少,T6I4峰时效态合金的裂纹源数目次之,而T6峰时效态合金的裂纹源数目最多;此外,与T6时效相比,T6I6和T6I4峰时效态合金的疲劳寿命均明显增加,其中T6I6峰时效态合金疲劳寿命的增幅最大。The effect of interupted aging treatments（T6I4 and T6I6） on the tensile mechanical properties and fatigue properties of 7050 alloy were investigated by using hardness measurement, mechanical tensile test, transmission electron microscopy（TEM） and fatigue performance test. The results show that the yield strength and tensile strength of T6I6 aged alloy increase by about 5.2 MPa and 10.6 MPa, respectively compared with T6 aged alloy, and the elongation of T6I6 aged alloy also increases by 1.9%.The elongation of T6I4 aged alloy increases by 2.9% compared with that of T6 aged alloy, but its strength shows a slight decrease. In T6I4 and T6I4 aged alloys, η′ phase particles with high density evenly distributes at grain interior and η phase particles discontinuously distributes along grain boundaries. At the same loading condition, T6I6 aged alloy possesses the fewest crack initiation sites and T6 aged alloy has the greatest number of crack initiation sites. In addition, compared with T6 aged alloy, the fatigue lives of both T6I4 and T6I6 aged alloys increase. Among them, T6I6 aged alloy has the largest fatigue lives under the same loading condition.

关 键 词：7050铝合金 间断时效 疲劳寿命 微观组织 

分 类 号：TG146.2[一般工业技术—材料科学与工程]