Study on the deformation behavior of β phase in Ti-10V-2Fe-3Al alloy by micro-indentation

The Ti-10V-2Fe-3Al alloy composed of β phases was varied by the β-solution treatment. In order to characterize the indentation deformation behavior of β phase, the micro-indentation tests were conducted in the indenter load ranging from 50 mN to 450 mN and the loading rates range from 4.84 mN/s to 19.36 mN/s at ambient temperature. The influences of β-solution treatment temperature, loading rate and indenter load on the micromechanics properties were investigated. The results showed that both the micro-hardness and Young's modulus of β phase declined drastically with the increase of indenter load, while remained the same level when the indenter load was above 300 mN. It was observed that the specimen under β-solution treatment of 820 °C and the loading rate of 19.36 mN/s possessed a higher micro-hardness and Young's modulus than that of others. The plastic energy dissipation, which was significantly influenced by the β-solution treatment temperature and loading rate, increased with the growth of indenter load exerted on the specimens and can be expressed in a power-law function of indenter load for β phase. In addition, the average plastic energy dissipation density in the micro-indentation was a linear function of the micro-hardness and its decrease with indenter load is attributed to the decline of geometrically necessary dislocations (GNDs).