Cr₂O₃-Enhanced Al-4%Cu Alloys: Unveiling Microstructural Refinement and Superior Mechanical Performance

Abstract

Enhancing the mechanical performance of Al-Cu alloys through cost-effective alloying particle strategies remains a significant challenge in materials engineering.This study investigates the influence of Cr₂O₃ particle additions on the properties and microstructure of Al-4%Cu alloys by varying the Cr₂O₃ content from 0.75 to 2.25 wt% in 0.25 wt% intervals, representing a compositional approach not previously reported.Mechanical properties were evaluated using tensile, hardness, and impact tests, while microstructural evolution was examined using optical microscopy and scanning electron microscopy.The results were compared between Cr₂O₃-free alloys and Cr₂O₃-reinforced alloys.The findings reveal that the addition of Cr₂O₃ particles promotes significant grain refinement, contributing to notable improvements in the alloy's mechanical performance.The tensile properties (ultimate tensile strength, yield strength, and ductility) of the Al-4%Cu alloy increased markedly with increasing Cr₂O₃ content, showing improvements of 53.03%, 42.14%, and 38% within the 1.50-2.25 wt% range compared to the unreinforced alloy.However, hardness and impact energy decreased with increasing Cr₂O₃ content, with optimum values observed at 0.75 wt%.This work establishes a systematic and economically viable route for enhancing the mechanical properties of Al-Cu alloys through composition-optimized Cr₂O₃ particle additions, offering new insights into the design and development of high-performance lightweight materials.