Numerical investigation of heat input effects on additive manufacturing of molybdenum alloys

This study presents a three-dimensional numerical analysis to examine the effects of heat input (810, 900, 990, and 1080 (J/mm)) on the material flow material, heat transfer behaviors, residual stress, and distortion during multilayer deposition of Titanium-zirconium-molybdenum (TZM) alloys. Transient simulations focused on the first two and last deposited layers, predicting the shape and size of the molten pool. The results illustrate that arc force plays a critical role in influencing the material flow for each layer's deposition. Among the heat transfer modes, conduction dominates over radiation and convection. The temperature gradient, distortion, and residual stress of the WAAM-TMZ specimens deposited under various heat inputs were evaluated. The lowest heat input (810 J/mm) resulted in the minimum distortion along the height direction, attributed to the smaller temperature gradient and more uniform temperature distribution, leading to uniform dispersion of stress and reduced final distortion. The highest yield strength (195 MPa) and elongation (1.28 ± 0.08 %) were observed in samples fabricated with the heat input of 900 J/mm. The outcome of this research is to develop an effective procedure to analyze the thermomechanical properties of wire arc additive manufacturing of refractory alloys.