On the nucleation and interaction mechanisms of hexagonal close packed (HCP) martensite in a Fe50Mn30Co10Cr10 high entropy alloy

LP Ding and YX Liang and YY Weng and J Tu and ZH Jia and Q Liu and T Pardoen and H Idrissi, ACTA MATERIALIA, 296, 121293 (2025).

DOI: 10.1016/j.actamat.2025.121293

The nucleation and interaction mechanisms of hexagonal close packed (epsilon-HCP) martensite in a Fe50Mn30Co10Cr10 high entropy alloy were investigated using atomic-resolution scanning transmission electron microscopy and molecular dynamic simulations. We demonstrate that the nucleation of epsilon-HCP is controlled by the activation of different mechanisms, including the six-plane and stair-rod cross-slip mechanisms. The nature of the intricate interaction mechanisms between two conjugated epsilon lamellae are highly dependent on the level of deformation and on the difference of thickness between the two crossing epsilon-HCP. Various absorption and transmission mechanisms of the incoming epsilon-HCP across the primary epsilon-HCP are revealed, involving local lattice rotation, the formation of new boundaries as well as stress induced twinning and phase transformation at the intersection sites. The synergy/competition between these mechanisms is discussed and compared with recent literature. These findings shed new light on the elementary mechanisms at the origin the remarkable strain hardening capacity of this category of high entropy alloys.

Return to Publications page