Grain-scale strain mapping for analysis of slip activity in polycrystalline B2 RuAl

Abstract

Strain development in a single phase polycrystalline B2 RuAl alloy has been studied at the local microstructural scale via a high-resolution surface displacement mapping technique. Significant heterogeneity of straining is observed within individual grains and among neighbouring grains. Strains accumulated in a self-similar manner at the grain scale during stepped loading experiments. Schmid factors for the possible slip systems were calculated using grain orientation data collected by electron back-scattered diffraction (EBSD). Considering the two major active slip systems identified in RuAl, i.e. 〈 100 〉{110} and 〈 110〉{110}, activity on the 〈 110〉{110} slip system dominated the local straining behaviour within the grains investigated. Complementary TEM dislocation analyses were performed by removing foils from targeted representative grains using a focused ion beam (FIB) system. A higher density of 〈 110〉 dislocations compared to 〈 100 〉 dislocations were observed in the most heavily strained grain.