Transactions of Nonferrous Metals Society of China The Chinese Journal of Nonferrous Metals

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中国有色金属学报

ZHONGGUO YOUSEJINSHU XUEBAO

第22卷    第4期    总第157期    2012年4月

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文章编号:1004-0609(2012)04-1025-08
双级时效制度对6156铝合金组织和性能的影响
张海锋,郑子樵,钟  申,罗先甫,钟  警

(中南大学 材料科学与工程学院,长沙 410083)

摘 要: 采用拉伸力学性能测试、电导率测定、晶间腐蚀实验及透射电镜分析等手段研究双级时效处理条件下6156铝合金的力学性能、电导率、晶间腐蚀和显微组织结构,采用正交实验优化双级时效工艺。结果表明:在本研究范围内,6156铝合金双级时效的四因素中第一级时效制度对合金的力学性能和电导率影响不大,第二级时效温度和时间是影响合金最终性能的主要因素。对于6156铝合金,最佳双级时效工艺为(175 ℃,6 h)+(210 ℃,5 h),相对于T6态,合金强度稍有降低,电导率上升,腐蚀类型也由晶间腐蚀转变为点蚀,腐蚀深度明显变浅。电镜观察结果表明:双级时效处理后,晶内析出大量的Q′相,晶界析出相球化且析出相之间的间距增大,呈断续分布,无沉淀析出带(PFZ)变宽,这种微观结构能有效提高6156合金的电导率和腐蚀性能,同时使合金具有较高的强度。

 

关键字: 6156铝合金;双级时效;力学性能;电导率;晶间腐蚀;微观组织

Effects of two-step aging treatment on
microstructure and properties of 6156 aluminum alloy
ZHANG Hai-feng, ZHENG Zi-qiao, ZHONG Shen, LUO Xian-fu, ZHONG Jing

School of Materials Science and Engineering, Central South University, Changsha 410083, China

Abstract:The effects of two-step aging treatment on the mechanical properties, electrical conductivity, intergranular corrosion and microstructure of 6156 aluminum alloy were investigated by means of tensile, conductivity measurement, intergranular corrosion experiments and transmission electron microscopy (TEM). The orthogonal test results show that the pre-aging has no obvious effect on the mechanical properties and electrical conductivity, and the second step aging temperature and time are the key factors in double aging parameters, which mainly decide the final properties of 6156 alloy. Under the optimum two-step aging treatment of (175 ℃, 6 h)+(210 ℃, 5 h), the ultimate strength decreases slightly and the electrical conductivity increases. The mode of corrosion changes from intergranular corrosion to pitting corrosion while the corrosion depth decreases obviously. The TEM observation results show that after two-step aging treatment, there are plenty of Q′ precipitates in matrix, and the coarse and isolate precipitates present in grain boundaries and the PFZ is broaden, which contribute to improve the electrical conductivity and corrosion resistance while the tensile strength decreases a little.

 

Key words: 6156 aluminum alloy; two-step aging; mechanical properties; electrical conductivity; intergranular corrosion; microstructure

ISSN 1004-0609
CN 43-1238/TG
CODEN: ZYJXFK

ISSN 1003-6326
CN 43-1239/TG
CODEN: TNMCEW

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