回归再时效热处理对7046铝合金显微组织与性能的影响

Effects of Retrogression and Re-aging Treatment on Microstructure and Properties of 7046 Aluminum Alloy

采用室温拉伸试验、极化曲线测试、透射电镜(TEM)等分析方法,研究了回归再时效(RRA)热处理过程中回归温度、回归时间对7046铝合金组织和性能的影响。结果表明,适当的RRA工艺可使合金具有良好的耐腐蚀性能,强度上也不低于T6态合金。经120℃×24 h预时效+180℃×15 min回归+120℃×24 h再时效的RRA工艺处理后,合金综合力学性能达到最优,抗拉强度、屈服强度分别为490.3 MPa、467.8 MPa,高于T6态的487.1 MPa、452.7 MPa;同时耐腐蚀性能也有了显著的提升,自腐蚀电流密度为8.616×10^(-7)A/cm^(2),为T6态的18.9%。

Effects of retrogression temperature and time on microstructure and properties of 7046 aluminum alloy were investigated by means of tensile test,potentiodynamic polarization test and TEM observation.The results indicate that desirable corrosion resistance can be obtained after proper RRA treatment,and the strength is close to that of T6 treated ones.The optimal properties are achieved after pre-aging at 120℃for 24 h,followed by retrogression at 180℃for 15 min and re-aging at 120℃for 24 h,where the tensile strength and yield strength reach 490.3 MPa and 467.8 MPa,respectively,which are higher than those of the T6-treated ones(487.1 MPa and 452.7 MPa).Moreover,the corrosion resistance is enhanced significantly,where the self-corrosion current density is 8.616×10^(-7)A/cm^(2),which is 18.9%of T6-treated specimens.