Analysis of Hardness Homogeneity in Pure Niobium Subjected to Equal Channel Angular Pressing

Abstract

This study investigated the evolution of hardness homogeneity of pure niobium subjected to equal channel angular pressing (ECAP) through microhardness measurements. Niobium samples were deformed via ECAP die with channel angle of Φ = 90° and curvature angle Ψ = 0° using Bc processing route at room temperature. Deformations occurred up to 8 passes, and hardness was measured at the longitudinal sections in the samples. The ECAP process increased the hardness by 55% between the 1st and 8th passes. The results demonstrate that hardness homogeneity was reached after six passes considering the steady-state of deformation.

Fig. 2 Color-coded contour maps of the microhardness values recorded on the longitudinal planes of the Nb without deformation (a) and deformed Nb with (b) 1, (c) 2, (d) 4, (e) 6, and (f) 8 passes.