A novel approach to thermal modelling and analysis in direct energy deposition for M2 steel alloy

Metal additive manufacturing (MAM) with its high material utilization efficiency to achieve the manufacturing of metal parts of complex shapes has great potential in the field of aerospace, medical, automotive and energy fields. MAM process generates large residual stress in the fabricated sample due to extreme mechanical, thermal and metallurgical interaction. Residual stress has a significant effect on dimensional stability. Thermal modelling of the MAM process is required to evaluate and implement the correct optimized process parameters for the quality fabrication module of industry. Thermal modelling is utmost necessary to fulfil the design for additive manufacturing (AM) of direct energy deposition (DED). Here, the fast design feedback loop is compiled by thermal modelling which reduces error in manufacturing. Thermal modelling of the DED AM process is carried out. As the material is temperature dependent, this depicts all the mechanical properties of the material given in the thermal modelling. Residual stress is generated, which has a significant effect on the dimension stability, corrosion resistance, crack growth resistance and mechanical properties of the fabricated sample through DED MAM. The present study performs a numerical simulation modelling for temperature-dependent M2 steel material as powder and SS304 as the substrate for the residual stress and temperature distribution of the defined laser power. The heat generated by laser power, i.e. Double Ellipsoidal Goldak's heat model is defined using Python script in the study. The study uses 800 W laser powers which generated a maximum residual stress of 179.9 MPa and yield stress of 321.7 MPa for the time interval of 50 s and also gives a maximum nodal temperature of 2233 K. The simulation will give us the details about the stresses of the material prior to development, i.e. without printing the actual component and will help to remove defects or printing failure to produce high-quality parts.