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MM: Fachverband Metall- und Materialphysik

MM 7: Mechanical Properties and Alloy Design II

MM 7.9: Vortrag

Montag, 9. März 2026, 18:00–18:15, SCH/A215

Martensitic phase transformation and anomalous hardening of CrMnFeCoNi high-entropy alloy deformed by high pressure torsion — Robert Chulist¹, Aurimas Pukenas², Anton Hohenwarter³, Reinhard Pippan³, and •Werner Skrotzki² — ¹AGH University of Science and Technology, Krakow, Poland — ²Technische Universität, Dresden, Germany — ³Montanuniversität, Leoben, Austria

Under hydrostatic pressure, the CrMnFeCoNi high-entropy alloy (HEA) undergoes a phase transformation from face-centered cubic to hexagonal close-packed. The onset pressure is strongly reduced by high pressure torsion (HPT): shear stress promotes partial dislocation slip. HPT of the low stacking fault energy HEA leads to a nanocrystalline microstructure. The hardness anomaly is due to the extreme nanostructuring, with grain boundary/interphase boundary sliding acting as predominant deformation mechanism: inverse Hall-Petch regime, in which hardness increases with increasing grain size. In submicrocrystalline materials, conventional Hall-Petch hardening dominates, i.e., hardness decreases with increasing grain size.

Keywords: High-entropy alloy; High pressure torsion; interface sliding