Designing Stronger, More Ductile High-Entropy Alloys

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Scientific Achievement

Novel, theory-guided design identified origins for transformation- and twinning-induced plasticity (TRIP/TWIP) to tune the strength and ductility in austenitic high-entropy alloys (HEAs), as was also confirmed experimentally.

Significance and Impact

Tuning single-phase HEAs properties enables control of strength-ductility properties for the design of stronger and economical materials.

Research Details
  • DFT methods integrated with full configurational averaging predicts average properties enabling theory-guided design for any complex solid-solution alloy with structural defects.
  • Confirmed composition and TRIP/TWIP behavior by single-crystal measurements: electron microscopy, selective-area diffraction, and electron-backscattered diffraction.
 

Martensitic transformation in FexMn80-xCr10Co10 High-Entropy Alloy,” P. Singh*, S. Picak, A. Sharma, Y.I. Chumlyakov, R. Arroyave, I. Karaman, and  Duane D. Johnson*,  Physical Review Letters 127, 115704 (2021).

 

high entropy alloys
FexMn80-xCr10Co10 (a) formation energy (Eform),  with FCC-to-HCP crossover (inset: phase map at x=40%Fe–FCC), (b) stacking-fault energy vs. x %Fe (inset: phase map at 45%Fe –HCP+FCC). Increased strength with two-phase coexistence (also observed) in narrow region of “x”.