Using a Hummingbird Scientific custom cryogenic SEM stage to cool an in-situ SEM indenter system, in-situ deformation of copper micropillars was investigated with in-situ Electron Backscatter Diffraction. Researchers at the University of California, Berkeley. Los Alamos National Lab, Brigham Young University, Pacific Northwest National Lab and Lawrence Berkeley National Lab showed that at cryogenic temperatures, stress-driven grain growth was observed during a series of elastic and plastic deformations. The results from their experiments provide direct evidence of a previously predicted phenomenon, in which grain coarsening after cryogenic loading when samples were not maintained at cryogenic temperatures between deformation and characterization.

Grain maps from the copper micropillar at each step in the compression experiment. Grain 2 contracts significantly between (b) and (c), between (c) and (d), and again between (g) and (h).  Copyright © 2020 TMS.

Reference: D. Frazer, J.L. Bair, E.R. Homer and P. Hoseman, Cryogenic Stress-Driven Grain Growth Observed via Microcompression with in situ Electron Backscatter Diffraction, JOM – The Journal of The Minerals, Metals & Materials Society, https://link.springer.com/article/10.1007/s11837-020-04075-x 

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