FEAST:Weld feasibility heat treatment studies of new superalloys

Purpose and goal:

The first objective was achieved, providing critical insights into welding parameters, microconstituents in the fusion zone, and post-weld heat treatment effects on grain growth and harmful constituents. The second objective, investigating hot cracking in G27 and VDM 780, is ongoing. Unexpected cracking in VDM 780, unrelated to hot cracking, was found and is under study, representing a significant additional discovery.

Expected results and effects:

The FEAST project will significantly impact the fabrication of aero-engine components by optimizing welding and heat treatment for G27 and VDM 780. Insights into weldability, microstructure, and hot cracking will improve manufacturing processes, leading to more reliable, durable components. In the long term, this will enhance safety and performance in aerospace and energy sectors, ensuring high material integrity and extended component lifespan.

Approach and implementation:

The project investigated the weldability of VDM 780 and G27 superalloys using Keyhole TIG and Laser Beam Welding. Welding trials focused on optimizing parameters to minimize defects and meet aerospace standards. In-depth microstructural analysis identified Nb-rich carbides and brittle Laves eutectics in the fusion zone, emphasizing the need for careful control. Heat treatment studies aimed at dissolving Laves eutectics and preventing grain growth were conducted to enhance weld integrity.