(1. 江苏工业学院 材料科学与工程学院，常州 213164；
2. 中南大学 材料科学与工程学院，长沙 410083)
摘 要: 采用拉伸试验、晶间腐蚀试验、金相及透射电镜观察，研究双级时效对6061铝合金拉伸性能和晶间腐蚀性能的影响。结果表明：6061铝合金经(180 ℃, 8 h)的T6峰值时效，抗拉强度和屈服强度分别为356 MPa和331.6 MPa，伸长率为13.7%，但出现严重的晶间腐蚀，腐蚀深度约为270 mm。在T6峰值时效的基础上进一步升高温度和延长时间进行二级时效，合金强度总体上呈逐渐降低趋势，电导率逐渐上升，腐蚀类型也由晶间腐蚀逐渐转变为点蚀，腐蚀深度明显变浅。对于6061铝合金，最佳双级时效工艺为(180 ℃, 8 h)+(210 ℃, 2 h)，抗拉强度为348.4 MPa，屈服强度为320.3 MPa，伸长率为11.3%，腐蚀类型为轻微点蚀，腐蚀深度约为50 mm。
关键字: 6061铝合金；双级时效；晶间腐蚀；微观组织
（1. School of Materials Science and Engineering, Jiangsu Polytechnic University, Changzhou 213164, China;
2. School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:Effects of two-step ageing treatment on tensile properties and intergranular corrosion(IGC)of 6061 aluminum alloy were investigated by tensile test, intergranular corrosion test, optical microscopy and TEM observation. The experimental results show that ultimate tensile strength, yield strength and elongation of 6061 alloy in T6 temper are 348.4 MPa, 320.3 MPa and 13.7%, respectively. However, the serious intergranular corrosion occurs with corrosion depth of about 270 mm. As a result of two-step ageing treatment, the strength decreases and the conductivity increases with the increase of two-step ageing temperature and time, but the mode of corrosion changes from intergranular corrosion to pitting corrosion (PC) while the corrosion depth decreases. Under the optimum two-step ageing treatment of (180 ℃, 8 h)+(210 ℃, 2 h), the ultimate strength, yield strength and elongation are 348.4 MPa, 320.3 MPa and 11.3%, respectively. The mode of corrosion is slight pitting with corrosion depth of 50 mm.
Key words: 6061 aluminum alloy; two-step ageing; intergranular corrosion; microstructure
