Evolution of the Surface Layer of the Al–15% Si–Y₂O₃ System after Combined Treatment

Abstract—Al–Si alloys are indispensable in various industries, such as aerospace and automotive ones, due to their high strength-to-weight ratio, high thermal conductivity, and corrosion resistance. These alloys often contain elements such as Si, Cu, Mg, and Zr, which improve their properties, and special compositions make it possible to increase strength and wear resistance and to improve a granular structure. The paper describes a combined modification of the surface layer of a hypereutectic Al–15% Si alloy, which consists in electroexplosive alloying by the Al–Y₂O₃ system followed by irradiation with a pulsed electron beam. Combined treatment is found to cause a multiple (by ~7.6 times) increase in the wear resistance of the modified silumin layer. The modified 35-μm-thick sample volume has a multilayer multielement multiphase structure and is reinforced with oxide nanoparticles. Pulsed electron beam irradiation of the surface of the silumin subjected to electroexplosive alloying is found not to bring about dissolution of an yttrium oxide powder: regions enriched in yttrium atoms are present at the sample surface. The revealed multiple increase in the wear resistance of the silumin subjected to combined treatment is thought to be caused by the formation of oxide nanoparticles in the surface layer.