Strengthening in multi-principal element alloys with local-chemical-order roughened dislocation pathways

High-entropy and medium-entropy alloys are presumed to have a configurational entropy as high as that of an ideally mixed solid solution (SS) of multiple elements in near-equal proportions. However, enthalpic interactions inevitably render such chemically disordered SSs rare and metastable, except at very high temperatures. Here we highlight the wide variety of local chemical ordering (LCO) that sets these concentrated SSs apart from traditional solvent-solute ones. Using atomistic simulations, we reveal that the LCO of the multi-principal-element NiCoCr SS changes with alloy processing conditions, producing a wide range of generalized planar fault energies. We show that the LCO heightens the ruggedness of the…

• NS
  National Science Foundation

  Awards: 1611064, 1804320, DMR-1611064, DMR-1804320, NSF-DMR-1804320
• UO
  University of Texas at Austin
• MA
  Maryland Advanced Research Computing Center
• CU
  Curtin University of Technology
• DO
  Division of Materials Research

  Awards: 1804320, DMR-1611064, DMR-1804320