Nano-indentation nanohardness and elastic modulus evolution of molybdenum processed by high-pressure torsion

Abstract

In this paper, high-pressure torsion (HPT) was conducted on pure molybdenum (Mo) (99.9 wt.%) under the 6 GPa pressure at room temperature with an angular velocity of 1 rev min−1. The samples processed by 1, 2, 5 turns of HPT were obtained. After 5 revolutions of HPT, the grains were significantly refined to 0.77 ± 0.17 µm and the main textures are {012}<121> and {001}<110>. The dislocation density of the sample after 2 turns of HPT deformation reaches to the maximum value. The elastic modulus of pure molybdenum after 5 turns of HPT has a great decrease. It is found that texture structures, dislocations and non-equilibrium grain boundaries can influence the elastic modulus evolution, and the latter two are the main factors.