Mechanisms of structural evolution of laminates with immiscible components under high-pressure torsion

The results demonstrate a gradual refinement of Mo phases; a greater degree of refinement is observed in the peripheral part of the disk-shaped HPT specimen, although some heterogeneity of the structure remains even at a gigantic degree of shear deformation accumulated therein.

The elemental distribution calculated from STEM EDX mapping as well as 3D reconstruction of atom probe tomography results shows a significant degree of mixing of the sample components at the atomic level, such that the concentration of copper in Mo reaches ~4.3 at. %; the corresponding concentration of molybdenum in Cu is ~6 at. %. These observations correlate with nanoindentation results showing an increase in the hardness of both phases due to strain hardening and solid solution strengthening, as well as grain refinement.