Investigation of aluminum surface properties in surface improvement process by electric discharge method

Due to the thermoelectric nature of the electrical discharge process, it is important to study the surface properties of the workpieces that are surface alloyed by this method. In this study, the effect of aluminum surface alloying process using Monell 400 electrode by electric discharge method on the workpiece surface mechanical properties has been investigated. To design the experiments, the pulse on time and pulse current were considered as input parameters and the surface residual stresses and Vickers indentation depth were considered as output parameters. In addition, the electromagnetic wave absorption of the surface alloyed layer was determined using the COMSOL simulation software. According to the obtained results, the Vickers indentation depth has the lowest value at the surface and with increasing distance from the surface, the amount of indentation depth increases. By increasing the pulse on time and pulse current, due to the increase in the amount of alloy elements (copper and nickel) diffusion to aluminum surface and thus improving the surface mechanical properties, the depth of the indentation decreases. Also, by examining the magnetic absorption in the surface layer using the simulation software, it was determined that the maximum amount of absorption of alloyed layer is in the range of 11-10.5 GHz.