Effect of solute content and temperature on the deformation mechanisms and critical resolved shear stress in Mg-Al and Mg-Zn alloys

TL;DR

This study investigates how solute atoms (Al and Zn) affect deformation mechanisms and shear stress in Mg alloys at different temperatures using micropillar compression tests.

Contribution

It provides new insights into the temperature-dependent effects of solutes on deformation and shear stress in Mg alloys, using high-throughput diffusion couple techniques.

Findings

Solute atoms increase size effects at 298 K and promote deformation localization.

Deformation becomes more homogeneous at 373 K, reducing micropillar size influence.

The solute content significantly affects the critical resolved shear stress for basal slip.

Abstract

The influence of solute atoms (Al and Zn) on the deformation mechanisms and the critical resolved shear stress for basal slip in Mg alloys at 298 K and 373 K was ascertained by micropillar compression tests in combination with high-throughput processing techniques based on the diffusion couples. It was found that the presence of solute atoms enhances the size effect at 298 K as well as the localization of deformation in slip bands, which is associated with large strain bursts in the resolved shear stress ($\tau_{RSS}$)-strain ($\epsilon$) curves. Deformation in pure Mg and Mg alloys was more homogeneous at 373 K and the influence of the micropillar size on the critical resolved shear stress was much smaller. In this latter case, it was possible to determine the effect of solute content on the critical resolved shear stress for basal slip in Mg-Al and Mg-Zn alloys.