Mechanical Behavior of Al-Al2Cu-Si and Al-Al2Cu Eutectic Alloys

In this study, laser rapid solidification technique was used to refine the microstructure of ternary Al-Cu-Si and binary Al-Cu eutectic alloys to nanoscales. Micropillar compression testing was performed to measure the stress-strain response of the samples with characteristic microstructure in the melt pool regions. The laser-remelted Al-Al2Cu-Si ternary alloy was observed to reach the compressive strength of 1.59 GPa before failure at a strain of 28.5%, which is significantly better than the as-cast alloy with a maximum strength of 0.48 GPa at a failure strain of 4.8%. The laser-remelted Al-Cu binary alloy was observed to reach the compressive strength of 2.07 GPa before failure at a strain of 26.5%, which is significantly better than the as-cast alloy with maximum strength of 0.74 GPa at a failure strain of 3.3%. The enhanced compressive strength and improved compressive plasticity were interpreted in terms of microstructural refinement and hierarchical eutectic morphology.