Microstructure, Phase Composition, Substructure and Residual Stress of Aluminum Alloy AK5M7 after Its Electro Spark Treatment
This paper presents the results of a study of the microstructure, phase composition, substructure parameters and residual stresses of the surface layer of the AK5M7 alloy after electrospark treatment (EST) using a copper-phosphorus electrode. EST energy constitutes the main variable parameter while the material under study is a multiphase alloy. The materials under phase study are: Al, Al2Cu and Cu3Al. It was found that an increase in the EST energy is accompanied by an increase in the proportions of Al2Cu and Cu3Al. As well as an increase in the magnitude of microstrains and residual stresses, followed by a decrease in the size of subblocks. For the aluminum phase, residual stresses are tensile, while for Al2Cu, they are compressive. Analysis of the intensities of the diffraction lines indicates the possibility of texture in the processed layer. An increase in the EST energy leads to a chaotic distribution of the grain orientation of the generated crystallographic phases. The results obtained are explained by nonequilibrium processes in the near-surface layer under high mechanical and thermal influences, accompanied by micrometallurgical processes.