Effects of Mn Content on Microstructure, Mechanical and Dry Sliding Wear Properties of Eutectic Al–Si–Cu Alloy

In the present study, effects of Mn content on microstructure, hardness, tensile and dry sliding wear properties of eutectic Al–Si–Cu alloy in as cast-state were investigated. Mn addition to the eutectic alloy results in the formation of α-Al₁₅Mn₃Si₂ phase in its microstructure. It was found that hardness of eutectic alloy increases continuously with increasing Mn content while its tensile strength and percentage elongation values decrease. It was also found that the friction coefficient and volume loss of eutectic alloy decrease as Mn content increases. Amongst the alloys, the lowest friction coefficient is obtained with Al–12Si–3Cu–2Mn alloy yet the Al–12Si–3Cu–1Mn alloy exhibits the highest wear resistance. Formation of adhesion layer, its oxidation and delamination were observed to be main wear mechanisms of Al–12Si–3Cu–(0–2)Mn alloys. These findings are explained in terms of formation of α-Al₁₅Mn₃Si₂ phase, and its cracking tendency effect.