Tensile and Fatigue Response of Steel Parts Fabricated by the Additive Friction-Stir Deposition Process

Abstract

Abstract Additive Friction Stir Deposition (AFSD) is a relatively new solid-state additive manufacturing (AM) process that utilizes frictional heating and plastic deformation for the layer-by-layer deposition of materials (e.g., metals and alloys). This study characterizes the mechanical behavior of AFSD-processed AISI 4340 steel parts under various tensile and fatigue loading conditions. A distinct scale of AISI 4340 steel specimens, namely the standard ASTM rectangular dog bone specimen is considered for the analysis. A finite element (FE) model is developed to predict the tensile and fatigue behavior of AFSD-processed steel AISI 4340 parts under multiple loading circumstances. The FE model can generate results for the von-Mises stress, strain, total deformation, fatigue life, factor of safety, and fatigue limit under various loading conditions. Experimental data for the tensile and fatigue responses are compared with the mechanical behavior obtained from the FE model at room temperature. The modeling results for the maximum tensile stress, deformation, and fatigue life exhibit excellent agreement with the experimental findings, which successfully confirms the validation of the FE model. The FE modeling for the fatigue analyses is conducted for a unit load ratio and by applying zero-based cyclic loads at different frequencies. Results from the current study successfully lead to generating a stress-life curve for the AFSD-processed AISI 4340 steel parts. According to the findings, the AFSD-processed components show higher strength than that of the parts created by conventional manufacturing techniques. In all cases, the AFSD specimens show extended lifespan compared to the conventionally manufactured specimens.