Backstress from dislocation interactions quantified by nanoindentation load-drop experiments

This is a Preprint and has not been peer reviewed. This is version 1 of this Preprint.

Downloads

Download Preprint

Authors

Christopher A. Thom, Lars N. Hansen, David L Goldsby, Kathryn M Kumamoto

Abstract

Recent work has identified the importance of strain hardening and backstresses among dislocations in the deformation of geologic materials at both high and low temperatures, but very few experimental measurements of such backstresses exist. Using a nanoindentation load drop method and a self-similar Berkovich tip, we measure backstresses in single crystals of olivine, quartz, and plagioclase feldspar at a range of indentation depths from 100–1750 nm, corresponding to densities of geometrically necessary dislocations (GND) of order 1014–1015 m-2. Our results reveal a power-law relationship between backstress and GND density, with an exponent ranging from 0.44 to 0.55 for each material, in close agreement with the theoretical prediction (0.5) from Taylor hardening. This work provides experimental evidence of Taylor hardening in geologic materials and supports the assertion that backstress must be considered in both high- and low-temperature deformation.

DOI

https://doi.org/10.31223/X5Z88W

Subjects

Physical Sciences and Mathematics

Keywords

olivine, transient creep, backstress

Dates

Published: 2020-11-13 17:00

License

CC BY Attribution 4.0 International

Add a Comment

You must log in to post a comment.


Comments

There are no comments or no comments have been made public for this article.