Modeling residual stresses of functionally graded deposits using the PTAAM

Abstract

Abstract High maintenance costs due to significant abrasive wear of components is experienced in the energy and mining sectors despite the current use of tough and hard coatings. During the coating process significant tensile residual stresses may build up and result in premature failure of a component. These tensile stresses can be reduced by adopting functionally graded structures of the composite. The main goal of the present study is to design an ideal material gradient in the additively manufactured composite using the plasma transferred arc (PTA) with a WC-Ni alloy graded in WC. To develop a comprehensive analysis of the functionally graded deposit, the thermal history of the WC and Ni alloy powders are first simulated as they travel through the plasma and deposit on the substrate. The initial temperature of each deposited bead depending on the WC content is deduced. These results are used as an input to predict the temperature and stress history of the solidifying deposit. Thermal stresses are computed and trends of residual stresses are obtained as a function of the WC gradient selected. The trends obtained are compared quantitatively before concluding on the most favorable gradient for this wear resistance application.