An integrated computational framework for high energy beam welding

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Modelling high-energy manufacturing processes requires a multi-step approach. Electron (EBW) and laser beam (LBW) welding are utilized for the purpose of high efficiency and precision manufacturing. These welding techniques are proven to be the most efficient on dissimilar metals. This research aims to create a framework where thermal fluid flow (TFF) models are integrated along the crystal plasticity finite element method (CPFEM) to simulate EBW and LBW processes. The framework will help understand the interplay between the chemical composition of low transformation temperature (LTT) alloy fillers, martensitic transformation, and manufacturing parameters. Phase field fracture (PFF) simulations will be used to understand the probability that microcrack forms at a specific location in the welded joint depending on the manufacturing parameters, such as the beam power and scanning speed. In later stages, these simulations will be used to optimize the beam parameters and the chemical composition of the materials to increase the strength of the welded joint. Following points represent a summary of the aims of this research: 1. Estimation and analysis of the formation of residual stresses at the micrometer length scale from the welding line. 2. Role of martensitic transformation and its relationship to the chemical composition profile along the welding line. 3. Integration of TFF and grain growth CPFEM to model the process. 4. A parametric model to understand and optimize the material composition, scanning speed, beam power and type of filler for an improved strength and ductility. This project will help understand the combined effect of manufacturing parameters and alloy composition of the parent metal and filler wire on the mechanical and fracture properties of the final components. This is particularly important for EBW, which has often been used without filler, while its usage is expected to improve the welded joints substantially. The computational tool developed will help to optimize the EBW and LBW processes and to produce welded joints with an increased lifetime by finding the manufacturing conditions that minimize residual stress. Metallic components that can last longer can reduce the replacement cost and reduce the emissions necessary to fabricate new components. The safety of vehicles and reliability of power plants for energy generation will be improved. Because of their prediction capabilities, computational methods can show the potential of the high energy beam technology in sectors in which it has not already been applied. This is particularly important because of the substantial cost of the equipment. Easy-to-use computational tools will eliminate the need for expensive experimental trial and error procedures.The application of the computational tool will not be limited to EBW but will also be useful for laser powder-bed fusion, a widely used AM technique. The time between discovering new alloys and evaluating the corresponding welding methods will be shortened.