(中南大学 材料科学与工程学院,长沙 410083)
摘 要: 通过显微硬度测试、拉伸实验、扫描电镜和透射电镜观察,研究微量Sn对Al-2.5Cu-1.5Mg(质量分数,%)合金的力学性能及微观组织演变的影响。结果表明:在Al-2.5Cu-1.5Mg合金中添加少量Sn能提高合金第二阶段的时效硬化和强化效果,微量Sn能够显著地提高合金的塑性,含Sn合金的峰时效伸长率能达到20.5%;经150 ℃时效1 000 h后,合金的伸长率仍有10.5%;微量Sn的添加能促进Al-2.5Cu-1.5Mg合金中S相析出,并能抑制其粗化。
关键字: Al-2.5Cu-1.5Mg合金;铝合金;时效特性;显微组织;Sn
(School of Materials Science and Engineering, Central South University, Changsha 410083, China)
Abstract:The effects of trace Sn additions on the ageing behavior and microstructure evolution of Al-2.5Cu-1.5Mg alloy were investigated by the microhardness test, tensile test, SEM and TEM. The results indicate that the trace Sn addition can increase the hardening and strengthening of the second stage of ageing. Adding trace Sn can significantly improve the ductility of Al-2.5Cu-1.5Mg alloy, the elongation of Sn-containing alloy at peak aged is 20.5%, and the alloy elongation is still 10.5% after aged at 150 ℃ for 1 000 h. The trace Sn addition can promote S phase precipitate and inhibit the S phase coarsen at over-aged.
Key words: Al-2.5Cu-1.5Mg alloy; aluminum alloy; ageing characteristics; microstructure; Sn