Exploring Crystal Plasticity Via Far-Field 3dxrd

A specimen of Ti-7%A1 alloy was subject to tensile deformation in situ at APS 1-ID-C. Within it, a neighborhood containing 20 complete grains was indexed in the annealed state and subsequently tracked at several applied stresses during in situ loading, both preceding and following the macroscopic yield stress. The stress states of each grain were observed to reorient significantly post yield despite the fact that their average remained close to the applied uniaxial stress. To aid in interpreting the experimental results, a virtual realization of the neighborhood was created using a finite element mesh. Each individual grain was represented by similar to 5000 hexahedral elements. Ensemble averaged resolved shear stresses were calculated over the neighborhood from both the experimental and simulated data. Despite the lack of intra-granular resolution in the experiment and with the aid of the simulated data the resolved shear stresses projected on several slip system families are shown to statistically capture the associated critical resolved shear stresses. This important result implies that the far-field 3DXRD method may be applied to the study of specific of slip system activity in embedded neighborhoods of grains subject to thermomechanical processing in situ.