Effects of Solution Treatment on Mechanical Properties and Microstructure of Al-Cu-Mg Alloy with Ag Addition

Effect of solution treatment on mechanical properties and microstructure of Al-Cu-Mg alloy with Ag addition was studied by using optical microscopy(OM),scanning electron microscopy(SEM),transmission electron microscopy(TEM),differential scanning calorimeter(DSC),and tensile test.Results show that the most suitable solution treatment process of the alloy is solutionizing at 515℃ for 1.5 h.After aging treatment at 185℃ for 4 h,tensile strength and elongation of the alloy are 503 MPa and 12.3%,respectively.The mechanical properties of the alloy increase first with increasing solution temperature and time,then decrease with solution temperature over 515℃(holding time is 2h)or solution time(solution temperature is 515℃) longer than 1.5 h.The lower solution temperature and less solution time result in a less re-solution of excess phases and produce a lower strength of the alloy.However,too high solution temperature and excessive solution time easily lead to over-burn of the specimens.The over-burned temperature of the alloy is demonstrated at 525.9℃.The solution temperature has stronger influence on mechanical properties and microstructure of this alloy than the solution time.