Influence of temperature on the strain rate sensitivity and deformation mechanisms of nanotwinned Cu

TL;DR

This study investigates how temperature affects the strain rate sensitivity and deformation mechanisms of nanotwinned copper, revealing increased sensitivity and consistent dislocation slip mechanisms across a temperature range.

Contribution

It provides new insights into the temperature-dependent deformation behavior and mechanisms of nanotwinned Cu, highlighting its enhanced strain rate sensitivity compared to coarse-grained Cu.

Findings

Strain rate sensitivity increases with temperature.

Deformation mechanism remains confined dislocation slip and pile-ups.

Enhanced sensitivity compared to coarse-grained Cu.

Abstract

The mechanical behavior of nanotwinned Cu was studied through indentation creep and constant strain rate indentation tests from 25 $^\circ$C to 200 $^\circ$C. The results showed an enhanced strain rate sensitivity of nanotwinned Cu with temperature, which was higher than that found in coarse-grained Cu. Transmission electron microscopy revealed the same deformation mechanism in the whole temperature range: confined dislocation slip between coherent twin boundaries and formation of dislocation pile-ups at the coherent twin boundaries. The mechanisms responsible for large increase in strain rate sensitivity of nanotwinned Cu with temperature were discussed to the light of experimental observations.