Characterization of Bulk Lamellar Accumulative Roll Bonded (ARB) Copper-Niobium Composites across the Length Scale.

摘要

In this work, the microstructure of Accumulative Roll Bonded (ARB) samples is investigated and compared to previously prepared Physical Vapor Deposition samples (PVD). The ARB technique was used to prepare samples across several length scales, from 60 microns down to tens of nanometers. Several samples within this length scale were chosen for investigation.;Given an understanding of the bi-material interface evolution under severe plastic deformation, selected mechanical properties (Hardness and Elastic Modulus) are investigated.;To investigate the Heterophase Interface Character Distribution (HICD), i.e. the full five-parameter description of interfaces at a heterophase interface, grain orientation maps were used. The method, described within, determines the orientation relationships (ORs) and 3D interface normal vectors of the Cu-Nb interface. Kurdjumov-Sachs and Nishiyama-Wasserman misorientations were investigated based on misorientation distribution plots (MDFs) for the composites, and it was observed that the makeup of the interfaces evolves with layer thickness for the ARB composites. {112}Cu/{112} Nb ORs are preferred in thicker layers, whereas {112}Cu//{112} Nb dominance occurs for the thinnest layers, with a transition at intermediate layer thicknesses (ℓ). This differs from the Kurdjumov-Sachs orientation relationship {111}Cu//{110}Nb observed for PVD composites. The interfaces occur with the lowest minimum energy configuration, but constrained by the texture associated with the samples.