Distinguishing contributions of ceramic matrix and binder metal to the plasticity of nanocrystalline cermets

Abstract

Using the typical WC–Co cemented carbide as an example, the interactions of dislocations within the ceramic matrix and the binder metal, as well as the possible cooperation and competition between the matrix and binder during deformation of the nanocrystalline cermets, were studied by molecular dynamics simulations. It was found that at the same level of strain, the dislocations in Co have more complex configurations in the cermet with higher Co content. With loading, the ratio between mobile and sessile dislocations in Co becomes stable earlier in the high-Co cermet. The strain threshold for the nucleation of dislocations in WC increases with Co content. At the later stage of deformation, the growth rate of WC dislocation density increases more rapidly in the cermet with lower Co content, which exhibits an opposite tendency compared with Co dislocation density. The relative contribution of Co and WC to the plasticity of the cermet varies in the deformation process. With a low Co content, the density of WC dislocations becomes higher than that of Co dislocations at larger strains, indicating that WC may contribute more than Co to the plasticity of the nanocrystalline cermet at the final deformation stage. The findings in the present work will be applicable to a large variety of ceramic–metal composite materials.

Frequency Characteristics of High Strain Rate Compressions of Cf-MWCNTs/SiC Composites

“…Nevertheless, when exposed to high-velocity impacts, FCMCs often fail due to severe fractures, resulting in substantial structural impairments. Consequently, an in-depth understanding of FCMCs' fracture behavior under high-strain rate conditions is critical for improving their impact resistance through structural and compositional enhancements [1][2][3][4][5].…”

Effect of Laser Processing Parameters on Microstructure, Hardness and Tribology of NiCrCoFeCBSi/WC Coatings

“…It is widely recognized, as well, that cemented tungsten carbide, which is usually used in coatings, has some degree of plasticity, especially when compressive loads are applied [4]. Moreover, it is shown that at the later deformation stage dislocations' density of WC in cermet dominates, indicating a more important WC role in the plasticity than a role of a metal binder [5]. This gives an advantage to WC over brittle hard materials.…”