Microstructure characterisation of multi-principal element alloys welds produced by electron beam welding

This work explores the feasibility of producing bead-on-plate welds of a CrCoNi medium entropy alloy and a CrMnFeCoNi high entropy alloy using electron beam welding. The alloys were welded in two states: one in an as-cold-rolled condition and the other in an annealed condition. In addition, the materials are welded with two different parameters. The FCC microstructure of the welds is investigated using scanning electron microscopy assisted by energy-dispersive X-ray spectroscopy and electron-backscattered diffraction. The impact of the weld on the microstructure is discussed. The heat-affected zone is negligible for the annealed condition of both medium and high entropy alloys since there is no driving force for recrystallisation and the exposure time to high temperature is insufficient for grain coarsening. The texture formed in the fusion zone is also discussed and compared to the texture in the base metal and the heat-affected zone. Although the grain growth along the (100) crystallographic direction is preferential in all cases, the crystallographic texture type differs from each weld. Higher hardness values are measured in the medium entropy alloy's base metal and fusion zone than in the high entropy alloy. & COPY; 2023 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Automated summary

This study investigates the feasibility of electron beam welding in producing bead-on-plate welds of CrCoNi and CrMnFeCoNi medium and high entropy alloys. The alloys are welded in two different states, namely, as-cold-rolled and annealed conditions, with two different parameters. The FCC microstructure of the welds is examined, and the impact on the microstructure is discussed. The heat-affected zone is negligible in the annealed condition due to the absence of recrystallization and insufficient exposure time to high temperature for grain coarsening.