Laser and arc weld methods for direct metal deposition of Waspaloy

Laser and electric arc are widely known heat sources used in the joining of metals. High Power Diode Laser (HPDL) and Tungsten Inert Gas (TIG) were used in this investigation. As they are additive welding processes with additional material supplied by filler wire the processes can be viewed as a metal deposition technique. If used with an appropriate manipulation system it can be used to build three-dimensional metallic parts for rapid prototyping or rapid manufacture. Complex components for use in aero engine systems can have very long manufacturing lead times when made by conventional processes, this is a severe hindrance during the product development cycle and the ability to use layer-by-layer methods of metal deposition would be very useful. The properties of many aerospace alloys are very sensitive to the production methods used so the use of alternative methods of manufacture has to be carefully considered and the property/process relationship understood. In this preliminary study, change of process parameters throughout building various layers of Waspaloy deposit was observed and the effect of metallurgical and mechanical properties of the deposits were analysed. The results suggest that the layer-by-layer deposition causes dynamic changes in the microstructure and geometry of the substrate and the previous deposited layer mainly due to heat transfer. This is more crucial when depositing Waspaloy because the temperature gradient during the deposition process affects the growth of gamma prime (γ′) precipitates and carbide particles which has an important impact on the mechanical properties of the material. Future work on process modelling will be carried out.