Use of Novel Welding Technologies for High-Entropy Alloys Joining

Abstract:

Laser beam welding and friction stir welding of high entropy alloys (HEA) of the CoCrFeNiMn system were studied. The HEAs were produced by self-propagating high-temperature synthesis (SHS). Along with the principal elements, Al, C, S, and Si impurities were detected in the composition of the alloys. The as-cast alloys consisted of columnar fcc grains with coarse precipitates of MnS and fine Cr-rich M₂₃C₆ carbides. Laser beam welding resulted in the formation of a defect-free weld joint. Precipitation of nanoscale B2 phase particles in the weld zone leaded to a pronounced increase in microhardness from ~150 HV of the base material to ~220 HV in the fusion zone. Friction stir welding (FSW) of a recrystallized state of the HEA with the average grain size of 3-5 μm resulted in the formation of a fine microstructure with a grain size of ~1.5 μm in the most strained area. Noticeable rise in strength and some decrease in ductility of the processed alloy in comparison with the initial condition can be associated with the formation of nanosized M₂₃C₆ carbides.

• Periodical: Materials Science Forum (Volume 941)
• Pages: 919-924
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.941.919
• Online since: December 2018
• Authors: Sergey Zherebtsov*, Nikita Stepanov, Dmitry Shaysultanov, Sergey Malopheyev, Igor Vysotskiy, Vladimir Sanin, Nikolai Kashaev, Rustam Kaibyshev
• Keywords: Friction Stir Welding, High Entropy Alloys, Laser Beam Welding (LBW), Mechanical Properties, Microstructure, Phase Stability

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