Microstructure and texture of a Ni-Mn-Ga alloy after hot extrusion and post heat treatments

The texture in a polycrystalline Ni50Mn29Ga21 magnetic shape-memory alloy deformed by high-pressure torsion (HPT) at 1173 K was investigated with high-energy synchrotron radiation. HPT changed the extrusion texture to a predominant slightly rotated cube {0 0 1} 1 0 0 and a weak F {1 1 0}1 0 0 component. During HPT the grain structure coarsened. Phase transformations during cooling from the deformation temperature led to coarse and fine sets of martensitic twin variants. The results are discussed with respect to deformation mode, grain growth and phase transformations