Investigating the mechanical and microstructural properties of Cr modified and recycled LM25 aluminium alloys

Abstract

Recycled aluminium alloys are increasingly favoured for their environmental and economic benefits; however, maintaining and enhancing their mechanical properties is critical. In this study, we investigate the mechanical and microstructural properties of recycled LM25 aluminium alloys modified with additions chromium (Cr). The introduction of Cr as a modifier is explored to enhance the strength and structural integrity of LM25 alloys, which are widely used in automotive applications. Scraps were recycled to form LM25 alloys, and chromium was added in powdered form at predetermined levels, followed by mechanical testing, wear, corrosion analysis, and microstructural analysis using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The results reveal a significant improvement in tensile strength and hardness with the addition of Cr, attributed to refined microstructures and the formation of stable intermetallic phases. Furthermore, the microstructural analysis indicated a notable reduction in grain size and a more uniform phase distribution in Cr-modified alloys. The Cr modification enhances the wear and corrosion resistance of the LM25 alloy by forming a passive barrier. These findings underscore the potential of Cr as an effective alloying element in recycled LM25 aluminium alloys, contributing to improved performance characteristics suitable for demanding applications.