Effect of aging heat treatment and extrusion process on mechanical properties of Al-3Mg-2.5Cu-xEr alloy

In this study, the effect of Al-30Er grain refiners, extrusion and heat treatment conditions on an Al-3Mg-2.5Cu aluminum alloy was studied. Different amounts of Al-30Er (0.5 wt.% Er, 1 wt..0% Er, 1.5 wt.% Er and 2 wt.% Er) were added to the molten alloy at 750 ◦C. The optimum level of Er was found to be 1 wt.%. Microstructural examinations and fracture surfaces were conducted by scanning electron microscopy coupled with an energy dispersive spectrometry. T6 heat treatment including quenching to room temperature and aging at 120 C for 24 h was employed to reach to the maximum strength. In order to eliminate the porosity inside the samples and improve the strength of the samples, the extrusion process was used with a ratio of 6 to 1. For the prototypes in the direction of extrusion, the diameter of the primary cylinder is 29 mm. By adding grain refiners and applying T6 heat treatment and extrusion process, a significant improvement in mechanical properties was achieved. The average ultimate tensile strength (UTS) of the samples before and after T6 heat treatment and extrusion process increased from 225 MPa to 602 MPa. Addition of one percent by weight of Er, applying heat treatment and extrusion process, caused a 167% improvement in tensile strength compared to the base aluminum alloy.