Electrical conductivity characterized at varying strains in spiral cut high-pressure torsion discs

TL;DR

This study investigates how electrical conductivity in copper discs processed by high-pressure torsion varies with strain, using a novel spiral cutting method to enhance characterization of strain-dependent properties.

Contribution

It introduces a spiral cutting technique to measure electrical conductivity at different strains in HPT-processed discs, providing new insights into strain-property relationships.

Findings

Electrical conductivity decreases with increasing strain.

Conductivity variation aligns with grain boundary evolution theories.

The spiral method improves strain-dependent property characterization.

Abstract

High-pressure torsion (HPT) imparts inhomogeneous strain to process discs with low strain in the center and higher strain at the outer edge. Microscopy and microhardness indentation have been used to characterize and correlate this inhomogeneity with strain, but similar exploration with other properties has been uncommon. In this work, the electrical conductivity of pure copper discs processed by HPT was characterized with respect to equivalent strain by cutting them into spirals with an incremental, monotonic increase in strain. Electrical conductivity varied with straining in agreement with the literature and expectations based on grain boundary evolution. The spiral conductivity testing method outlined in this work can improve characterization of HPT materials in future studies.