Volume 78, 1 October 2014, Pages 56-64

TL;DR

This study introduces a new experimental setup for in situ cryogenic testing of pure Sn micropillars, revealing distinct deformation mechanisms at different temperatures and orientations, advancing understanding of plasticity below the ductile-to-brittle transition.

Contribution

The paper presents a novel cryogenic testing method and compares deformation mechanisms of Sn micropillars at room and cryogenic temperatures for different orientations.

Findings

Dislocation plasticity dominates at room temperature.

Deformation twinning occurs at 142°C.

Deformation mechanisms are consistent across tested orientations.

Abstract

Characterizing plasticity mechanisms below the ductile-to-brittle transition temperature is traditionally difficult to accomplish in asystematic fashion. Here, we use a new experimental setup to perform in situ cryogenic mechanical testing of pure Sn micropillars at room temperature and at 142{\deg}C. Subsequent electron microscopy characterization of the micropillars shows a clear difference in the deformation mechanisms at room temperature and at cryogenic temperatures. At room temperature, the Sn micropillars deformed through dislocation plasticity, while at142{\deg}C they exhibited both higher strength and deformation twinning. Two different orientations were tested, a symmetric (100) orientation and a non-symmetric (451) orientation. The deformation mechanisms were found to be the same for both orientations