Microstructure and microhardness of melt-spun Al-25Si-5Fe-XCo (XÂ =Â 0, 1, 3, 5) alloys

► Microstructure of melt-spun Al-Si-Fe alloy with Co addition was studied. ► Co modifies the primary Si in rapidly solidified Al-Si-Fe alloy. ► Formation of spherical Si particles in Al-Si alloy by Co addition was reported. ► An optimum ratio of Si and Co for formation of spherical Si particles was suggested.