Designing Transformations in High-Entropy Ferritic Steels

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Ferretic steel charts and graphs.
For Cr0.20Fe0.35Ni0.10Al0.25Ti0.10, ferritic steel, (a) electronic dispersion, with chemical disorder broadening, (b) partial density of states, and (c) short-range order (SRO, in Laue units) along directions of BCC Brillouin zone. Peaks at H = (111) indicate strong B2 SRO dominated by Al–Ni pairs, and secondary ordering (from Al–Ti pairs) due to a weaker ordering peak at P = (½ ½ ½). Controlling peaks at H + P yield formation of L21 (Heusler) phase (both B2 and L21 are observed).
Scientific Achievement

Design of order-disorder transformations in high-entropy ferritic (Ti-Cr-Fe-Ni-Al) steels by a novel electron-based theory that identifies electronic origins for chemical ordering and how to control it.

Significance and Impact

Tuning the degree of short-range order in ferritic steels optimizes phase selection and mechanical properties in technological-useful structural alloys. 

Research Details
  • Electronic-structure based linear-response theory integrated with configurational averaging predicts ordering for complex solid-solution alloy, including ferritic steels.
  • Predictions for control (e.g., %Ti) agree with known and recent experiments.  

Prashant Singh &  Duane D. Johnson, “Designing order-disorder transformation in high-entropy ferritic steels,” Journal of Materials Research (2021). Invited by JMR Editors – Early Career Scholars in Materials Science 2022