Synergizing strength and plasticity in amorphous high-entropy alloys via heterogeneous interface and short-range order design

Heterogeneous interfaces and short-range order (SRO) are crucial yet underexplored microstructural features in amorphous high-entropy alloys (HEAs). To address the ubiquitous strength-plasticity trade-off in amorphous HEAs, this study employs Monte Carlo/molecular dynamics simulations to investigate the mechanical properties and microstructural evolution of amorphous CoNiCrFeMn HEAs across both random solid solution (RSS) and SRO structural regimes. The results demonstrate that introducing SRO structures alone significantly enhances the yield stress and Young's modulus of the alloys, but at the expense of drastically reducing plasticity. To overcome this limitation, we design amorphous/amorphous RSS/SRO multilayers featuring “heterogeneous interfaces” and systematically explore the synergistic effect of layer thicknesses and SRO degree on the mechanical responses. In these multilayers, the plastic deformation behavior of the alloys exhibits a strong dependence on the soft phase size ( h RSS ). As h RSS increases, the plastic deformation mode undergoes a transition: from shear band nucleation and propagation to homogeneous deformation, and ultimately to necking instability. Within the investigated geometric configurations (with a fixed h SRO of 10 nm), an optimal dimensional matching ( h RSS = 3nm) is identified to achieve an excellent synergy of high strength and high plasticity. Furthermore, an optimal SRO degree threshold is identified, at which moderate SRO promotes optimal mechanical matching between the soft and hard phases, effectively suppressing deformation localization. This study reveals the mechanistic control exerted by heterogeneous interfaces and SRO on the mechanical behavior of amorphous HEAs, providing structural design strategies and quantitative guidance for the development of novel high-performance amorphous HEAs.