Microstructural evolution and enhanced tribological performance of multi-component Al–Fe–Mn–Cu Alloys: A comparative study between conventional casting and laser powder bed fusion

This study investigates the influence of microstructural architecture on the tribological performance of multi-component Al-Fe-Mn-Cu alloys fabricated via conventional casting and Laser powder bed fusion (LPBF). While the cast alloys were characterized by coarse equilibrium intermetallic compounds (IMCs) such as plate-like Al 13 Fe 4 and rhombic Al 6 (Fe,Mn), the LPBF process yielded an ultrafine cellular matrix with homogeneously dispersed nanoscale IMCs Al 6 Fe. Mechanical testing revealed that LPBFed alloys exhibited significantly superior Vickers hardness, with the Al-2.5Fe-2Mn-2Cu alloy achieving a peak value of 146.67 HV, approximately 2.4 times higher than its cast counterpart. Sliding wear tests demonstrated a fundamental transition in wear regimes: the cast alloys suffered from severe adhesive wear and catastrophic delamination driven by the fragmentation of brittle, coarse IMCs, whereas the LPBFed specimens displayed stable hybrid wear behavior (abrasion and localized adhesion). Cross-sectional EBSD and SEM analyses confirmed that the LPBFed alloys prevented the formation of a brittle mechanically mixed layer by suppressing subsurface crack propagation. A comprehensive Performance Index validated that the synergistic addition of Mn and Cu in the LPBFed Al-2.5Fe-2Mn-2Cu system maximized wear durability. These findings underscore the potential of LPBF-induced microstructural refinement for developing high-performance, wear-resistant aluminum components for robotic structural applications.