Detektering av töjning och åldringssprickor med diffraktion

Hastelloy X is a solid solution strengthened nickel-based superalloy for high temperature applications. It is used in hot sections of gas turbines, where welding is commonly used as a joining technique during part production. However, laser welding of Hastelloy X has been found to cause heat affected zone liquation cracking. This is also a potential concern when using laser metal deposition with powder as feedstock material (LMDp), where multi-layer material deposition as during LMDp generally provide a greater risk of crack formation. The thermal profile and its effect on microstructure and mechanical properties is therefore a critical concern for the industrial partners in this project.

The combination of the complex metallurgy of the material and the multi-parameter environment of LMDp necessitates the development of a suitable process window tailored to both material and application. Being able to understand and control the material changes and effects on mechanical performance will enable the application of the technique in production and provide a more controlled and repeatable repair process of cast and welded gas turbine components. The project is therefore of great interest to producers of structural gas turbine components for aerospace (GKN Aerospace) and land-based applications (Siemens).

The aim, therefore, is to research the influence of LMDp process parameters on the thermal profile and the microstructure evolution of Hastelloy X within the framework of a repair operation. As a result, design recommendations will be developed to enable the use of LMDp of Hastelloy X in component production. The objective is also to enable the project leader to develop into an independent researcher and in co-production contribute towards development and innovation among participating partner companies. The project will also contribute to the development of the research and education of welding technology at University West.