Quantifying elastic strain near coherent twin interface in magnesium with nanometric resolution

Abstract

The localized plastic shear associated with deformation twinning induces both, dislocation emission and elastic strain fields near twin interfaces. In this work, we modified a standard peak-pair algorithm (PP) to extract the local elastic strain field associated with twins in Mg from the observed atomic structure. We also used nano-beam electron diffraction (NBED) method for comparison and to characterize the strain field at several positions inside and in the vicinity of a twin. The results reveal: (1) a much larger stress concentration near the basal-prismatic interface than at the coherent twin boundary; (2) a stress concentration in the matrix ahead of the twin tip that seems to be associated with dislocation pileups. This work provides insight at the nanometric scale about the elastic strain field associated with both elastic and plastic deformation in the vicinity of twin interfaces.