Influence of Composition and Processing on the Mechanical Response of Multi-Principal Element Alloys Containing Ni, Cr, and Co
Abstract
Conventional metal alloys are made up of one predominant base metal and smaller quantities of one or more additional alloying elements. Although this strategy has successfully produced all metals currently in use, a new multi-principal element paradigm is emerging in which highly-alloyed compositions lack a clear base metal. This foray into previously unexplored composition space has produced new alloys with excellent combinations of strength, ductility, and other properties, particularly when using 3d transition metal elements. This work concerns multi-principal element alloys comprising transition metals chromium, cobalt, and nickel.Key findings include a more detailed understanding of heterogeneous microstructures and their effect on alloy strength and ductility; new indications that deformation twinning may be unnecessary for high strain-hardening rates and good ductility; and elucidation of the discontinuous coarsening effect along grain boundaries in highly-alloyed CrCoNi-base materials like commercial superalloy 740H. These results can be broadly applied to other multi-principal element alloys and austenitic steels.
- Publication:
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Ph.D. Thesis
- Pub Date:
- 2019
- Bibcode:
- 2019PhDT........74S
- Keywords:
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- Materials science