Phenomenological Modeling of Distortions and Residual Stresses in Direct Energy Deposition of AISI M4 High Speed Tool Steel on D2 Substrate

This study aimed to develop a computational methodology to estimate the residual stress formation behavior followed by direct energy deposition of high-speed tool steel hard materials. First, evolutions of substrate distortions followed by the depositions of AISI M4 tool steel layers were investigated by experiments and the results were analyzed using the elasticity-based Stoney's approach. The results revealed significant additional distortion caused by the temperature gradient formed when depositing the first M4 layer. Distortions occurring on depositing the second and subsequent M4 layers could be approximated as linearly increasing with the total M4 layer thickness, indicating a stable inherent shrinkage strain for each layer deposition process. It was also clearly revealed that the elastic Stoney's approach is not capable of predicting the residual stress in the studied direct energy deposition system as significant plastic deformations are expected to occur. Based on the experimental observations, a phenomenological finite element (FE) model was developed considering the elastoplastic behavior of materials. The FE simulation results showed very good agreement with the experimentally measured distortions during the M4 deposition process in a wide range of deposition areas and thicknesses. Thus, the proposed model can be used effectively for controlling the distortions and analyzing residual stress evolutions during hard-facing or repairing processes using direct energy deposition.

Automated summary

This study aimed to develop a computational methodology to estimate the residual stress formation behavior followed by direct energy deposition of high-speed tool steel hard materials. Through experiments and finite element simulations, it was found that the proposed method is effective in controlling distortions and analyzing the evolution of residual stress.