Nano-mechanical testing of Al-Nb metal matrix composites consolidated by high pressure torsion after annealing

Abstract

Abstract Among different approaches for obtaining composite structures, one can distinguish the approach of severe plastic deformation that allows obtaining bulk structures from strongly dissimilar metals. The application of large strains is usually associated with grain refinement and, in some cases, with the formation of intermetallic phases, both factors contributing to the strength characteristics of the material. This work presents an investigation of nano-mechanical properties of an Al-Nb composite obtained by high pressure torsion and post deformational annealing. Measurements show that with an increase in the distance from the centre to the edge of the sample, the nanohardness increases from 2.4 to 3 GPa. Young’s modulus varies in the range from 182 to 197 GPa, which indicates the non-homogeneity of the composite sample. The Young’s modulus of the composite after high pressure torsion was found to be higher than that of pristine Al and Nb, which is probably due to the formation of the intermetallic Al3Nb phase, having an increased Young’s modulus according to ab-initio calculations.