Study of the evolution of the Cu/Nb interphase boundary by the molecular dynamics method

Abstract

The evolution of atomic structure of the interphase boundary for composites from immiscible Cu/Nb elements is studied by the molecular dynamics method. It is established that the planar interphase boundary is stable at temperatures up to 1200 K. Atomic dissolution of elements is not revealed in the entire examined temperature interval, and the components are mixed on the interphase boundary of finite curvature in the form of clusters and nanolamellas; moreover, the amorphous state is not formed in the process of migration of the interphase boundary.

Amorphous-Nanocrystalline Composites Prepared by High-Pressure Torsion

“…The appearance of an amorphous phase in the near-interface areas was first experimentally established in our investigation by the methods of direct-resolution TEM (Figure 13a,b) and XRD ( Figure 16). This confirms the hypothesis [48][49][50] on the possibility of the clustered structure of the regions containing simultaneously copper and niobium atoms. In a rather detailed scientific work [47], no amorphous phases have been detected in the Cu-Nb nanolaminates after SPD, but nonequilibrium supersaturated solid solutions of Cu-Nb (up to 1.5 at.…”

“…The energy anisotropy of the interface in a system of non-miscible elements was first studied in [48][49][50] by the example of molecular-dynamics simulation of Cu/Nb bicrystals. It was established that the mechanism of niobium dissolution in the copper matrix involves the formation of niobium clusters coherent with the matrix.…”

“…The observed [48][49][50] phenomenon of niobium cluster dissolution near the Cu/Nb interface of finite curvature is proposed as a physical explanation of the amorphization of such interface. Because of the lattice distortion by clusters, a sharp TEM image of the projection of close packed copper atom rows in the interface region disappears, and such regions are recognized as amorphous.…”