Effect of electron-plasma alloying on structure and mechanical properties of Al-Si alloy

Abstract

The paper reports on research into element and phase composition, micro-hardness and wear resistance of Al-Si alloy surface layer processed using the method of electron-plasma alloying. When electron-plasma alloying the surface layer of Al conductor is alloyed with Y2O3 powder portion by electric explosion and irradiated by electron beam with different densities of energy. The study has identified important structural transformations in the surface layer of the material irrespectively of electron-plasma alloying mode. The formed layer has a multi-element, multi-phase composition with sub-micro and nanocrystalline structure. Comparison of the modified layer with its primary structure has confirmed dissolution of Si inclusions and micron and submicron intermetallic compounds. The study has revealed a structure of high-speed cellular crystallization in the layer formed in the process of electron-plasma alloying and facetted inclusions, the relative concentration of which drops as far as from the modified surface. A significant drop of micro-hardness in layers has been identified. The findings also point at a sharp decrease in wear parameter in surface layers in comparison with the original state. Assessing transformations of frictional properties, micro-hardness and structure, it is concluded that they are results of nanocrystallization and Y enrichment of surface layers when electron-plasma alloying.