Microstructures and mechanical properties of mechanically alloyed V–4Cr–4Ti alloy dispersion strengthened by nano-particles

Nano-particle dispersion strengthened V–4Cr–4Ti with Y and TiC additions are manufactured via mechanical alloying (MA). The MA process was studied by clarifying the dissolution behaviors of alloying elements in V matrix. High temperature annealing at 1200 °C is carried out to modify the microstructures in the alloy. Tensile and creep tests at 700 °C are performed to evaluate the strengthening mechanisms based on solid solution hardening, grain size refining and nano-particle dispersion strengthening. Compared with the TiC additions, nano-particles formed in the fabrication procedure, such as TiN and Y2O3, can strengthen the alloy more evidently. Moreover, compared with TiN which has small number density but large size, Y2O3 distributing in large number density and smaller size, has higher thermal stability and contributes more to the strengthening at high temperature.