Advanced Ultra Super Critical (AUSC) fossil-powered power plants are operated at a temperature of more than 720 Degree Celsius, which limits the use of many materials for these applications. Applying precipitation-strengthened nickel-based superalloys increases the efficiency of AUSC boilers, decreasing the use of nonrenewable energy sources. Haynes 282 and IN740H are γ’ strengthened nickel-based superalloys alloys with excellent creep strength and weldability compared to other wrought nickel-based superalloys and are best-suited materials for AUSC power plant components such as combustors, turbine and exhaust sections, nozzle etc. These alloys are under consideration for replacing materials used for critical components used for aircraft engine components. However, the overall cost associated with manufacturing components using these superalloys are technically challenging and incurs significant overall cost. Hence the application of these superalloy materials are limited to the critical regions and austenitic stainless steel can be used in less critical regions. To facilitate the joining of these critical components, high-power beam processes such as Electron Beam Welding (EBW), Laser Beam Welding (LBW) and arc welding processes like Robotic Key Hole Tungsten Inert Gas Welding (Key Hole TIG) can be implemented. However, welding of nickel-based superalloys are prone to solidification, liquation and reheat cracking. Moreover, the dissimilar welding of these alloys is highly challenging because of differences in melting points, heat transfer rate, coefficient of thermal expansion, segregation of alloying elements, etc.

This work aims to study the effect of different welding processes such as EBW, LBW and keyhole TIG welding processes on the dissimilar material joining of Haynes 282 with IN740H and SS 321. Integrating the macro-FEM simulation with micro-scale phase field model will help in simulating the microstructural evolution of dissimilar weld joints. An ICME framework will also be developed to simulate the microstructure of dissimilar weld joints.