Graphene-enhanced sintering densification mechanisms in CoNiCrFeMn high-entropy alloys

Graphene-reinforced high-entropy alloys (HEAs) have emerged as promising candidates for advanced structural applications, yet the atomic-scale mechanisms through which graphene nanoplatelets (GNPs) modulate densification and microstructural evolution during spark plasma sintering (SPS) remain poorly characterized. This study employs molecular dynamics (MD) simulations to unravel the sintering behavior of CoNiCrFeMn HEA composites with GNPs, demonstrating that GNPs significantly enhance sintered densification. The underlying mechanisms involve synergistic effects: GNPs act as effective dislocation pinning sites, inducing high-stress regions that promote alloy particle rearrangement and pore elimination; sintered GNPs form a three-dimensional network, enabling efficient heat transfer and mechanical interlocking with the HEA matrix to accelerate atomic diffusion; and the active graphene-HEA interface reduces surface energy, facilitating grain nucleation and refinement. Experimental results validate the MD simulations. These findings establish a critical link between interfacial interactions at the atomic scale and macroscopic densification kinetics, providing insights for optimizing SPS parameters in graphene/HEA composite fabrication.