Descriptive tools for the analysis of texture projects with large datasets using MTEX : strength, symmetry and components

Abstract

This paper presents the background for the calculation of various numbers that can be used to characterize crystal-preferred orientation (CPO), also known as texture in materials science, for large datasets using the combined scripting possibilities of MTEX and MatLab w . The paper is focused on three aspects in particular: the strength of CPO represented by orientation and misorientation distribution functions (ODFs, MDFs) or pole figures (PFs); symmetry of PFs and components of ODFs; and elastic tensors. The traditional measurements of texture strength of ODFs, MDFs and PFs are integral measurements of the distribution squared. The M-index is a partial measure of the MDF as the difference between uniform and measured misorientation angles. In addition there other parameters based on eigen analysis, but there are restrictions on their use. Eigen analysis does provide some shape factors for the distributions. The maxima of an ODF provides information on the modes. MTEX provides an estimate of the lower bound uniform fraction of an ODF. Finally, we illustrate the decomposition of arbitrary elastic tensor into symmetry components as an example of components in anisotropic physical properties. Ten examples scripts and their output are provided in the appendix.

Evidence of phase nucleation during olivine diffusion creep: A new perspective for mantle strain localisation

“…In any case, we document extremely weak LPOs considering the amount of strain accommodated. For instance, one would expect J > 10 and M > 0.3 for a gamma strain higher than 3 (Hansen et al, 2014;Mainprice et al, 2015), whereas we never quantify higher than J = 2 and M = 0.1, irrespective of the amount of finite strain. GBS.…”

Stress evolution and associated microstructure during transient creep of olivine at 1000–1200 °C

“…Densities of pole figures of the CPO were normalized to a uniform distribution and contoured at intervals of 0.5 × uniform. The BA-index was introduced by Mainprice et al (2014) to characterize the symmetry of olivine pole figures [100] and [010].…”

Analysis of crystallographic preferred orientations of experimentally deformed Black Hills Quartzite

“…Unless otherwise specified, only the maps of the high-bulk-strain experiments w1092, w946 and w935 were analyzed (details in Heilbronner and Kilian, 2017). For data cleanup and processing, the MTEX toolbox by Ralf Hielscher was used (https://mtex-toolbox.github.io/; e.g., Bachmann et al, 2011;Mainprice et al, 2015). Single mis-indexed pixels were deleted and reconstructed together with single nonindexed pixels.…”