Stress induced martensite variants revealed by in situ high resolution electron backscatter diffraction (HR-EBSD)

Highlights: • In situ HR-EBSD was done to correlate stress induced phase transformation and stress fields. • A Schmid factor analysis was extended by the analysis of local resolved shear stresses. • Growth of an unexpected martensite variant near the grain boundary is observed. • Stress concentrations are shown to trigger the growth of the unexpected variant. In situ HR-EBSD during FeMnSi-based micro-pillar compression is used to correlate phase transformations and its underlying stresses. A simple experimental configuration containing two grains, one grain boundary and a uniaxial compression causes complex stress fields. Two out of three differently orientated stress induced martensite variants are expected to form due to high Schmid factors. To reveal the origin of growth of the third variant with a low Schmid factor, we calculate global stress maps and local resolved shear stress maps based on HR-EBSD measurements. Localized shear stresses at the grain boundary are identified to cause the growth of the not expected near grain boundary variant.