Publisher DOI: 10.1016/j.actamat.2018.03.009
Title: On a novel strain indicator based on uncorrelated misorientation angles for correlating dislocation density to local strength
Language: English
Authors: Guglielmi, Paula O. 
Ziehmer, Markus 
Lilleodden, Erica 
Issue Date: 15-May-2018
Source: Acta Materialia (150): 195-205 (2018-05-15)
Journal or Series Name: Acta materialia 
Abstract (english): We present a new method based on uncorrelated misorientation measurements by Electron Backscattered Diffraction (EBSD) to characterize the dislocation density of site-specific areas selected on a bulk material. Gold samples submitted to different degrees of pre-straining are analyzed. A new scalar misorientation parameter called the Characteristic Misorientation Angle (CMA) is derived from uncorrelated misorientation data and compared to the more conventional parameters Grain Average Misorientation (GAM) and Grain Orientation Spread (GOS). We show that CMA is nearly independent of the scan step size and is more sensitive to plastic deformation than GAM and GOS. A coupled effect of local plastic strain and area size is observed on the measured values of CMA. Based on that, values of dislocation density are determined for site-specific areas whose strengths, as defined by the hardness at first pop-in, are subsequently measured by spherical nanoindentation. Results show that the site-specific strength of gold decreases with increasing initial dislocation density. While previous studies have suggested the same trend, the present work offers a new approach to more quantitatively correlate local dislocation densities to the onset of plasticity, without the need for destructive TEM investigations or micro-sample fabrication.
URI: http://hdl.handle.net/11420/2913
ISSN: 1359-6454
Institute: Keramische Hochleistungswerkstoffe M-9 
Type: (wissenschaftlicher) Artikel
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