Process Optimisation and Tribological Behaviour Studies on Surface Modified Al 6061-T6 Alloy Deposited with WS2 Solid Lubricant Layer Through Electrical Discharge Approach

In this present work, an attempt has been made to deposit the WS2 layer on the Al 6061-T6 alloy surface through the electrical discharge deposition (EDD) technique. Specified deposition parameters, namely powder concentration (Cp), pulse-on time (Pon), and gap voltage (Vg) with various levels considered during the EDD process. The experimentation was performed for analysing the results of deposition parameters on material deposition rate (MDR), surface roughness (SR), microhardness (MH), layer thickness (LT), and surface characteristics of the WS2 layer were examined. The results addressed the various intermetallic compounds formed on the deposited surface. A multi-objective optimisation using Box–Behnken design of response surface methodology was utilised to conduct the deposition process. To predict and optimise the appropriate MDR, SR, MH, and LT, the quadratic model was developed using regression analysis and analysis of variance. Based on the developed model, the interaction effects of deposition parameters on the EDD process were explored. The optimal depositing parameters are determined by maximising the MDR and MH and minimising the SR and LT. The validation test results confirm that experimental data are good in agreement with the predicted results, and hence, the model is feasible to predict the responses adequately. The tribological study was carried out for the optimised condition, and surface characteristics on the worn-out surface were analysed. When compared to the base material, the obtained results show a lower coefficient of friction and specific wear rate.