Structure and mechanical properties of Ti-Cr-Al-Nb and Ti-Cr-Al-Nb-V multicomponent alloys

The empirical and semi-empirical models were used to analyze the phase-structural state of five- and four component alloys of the Ti-Cr-Al-Nb-V system. Two compositions of lightweight alloys were selected for experimental study: Ti₆₀Cr₁₁Al₇Nb₁₁V₁₁ and Ti₆₀Cr₁₁Al₇Nb₂₂ (at. %). Ingots of these alloys were obtained by argon arc melting method, and they were subjected to homogenization, deformation by rolling and subsequent annealing at different temperatures. The influence of annealing temperature on the phase-structural state of the alloys, their hardness, and mechanical properties during tensile tests has been studied experimentally. It was found that the change of phase composition and grain size during annealing in the temperature range of 700…900 °C practically does not affect the hardness and tensile strength of alloys. Annealing at 900 °C transforms the alloys into a single phase state with bcc lattice and significantly increases the elongation to fracture, which is about 30% for both alloys. In addition, the yield strength and tensile strength of the five-component alloy are noticeably higher than those of the four-component alloy. (author)