Elastic and mechanical properties of Ti–Nb–Zr based alloys

The elastic properties and mechanical characteristics of Ti–Nb₂₂–Zr₆ based alloys were calculated using the exact muffin-tin orbital method with the coherent potential approximation. Alloying by metals such as Hf, Mg and their combination were considered, and their concentration did not exceed 5 at.%. It was shown that addition of Hf and Mg leads to a decrease in Young’s modulus due to both size effect and electronic factor. The calculated Young’s modulus for the ternary Ti–Nb₂₂–Zr₆ alloy (70.1 GPa) is found in good agreement with experimental one (70 GPa). The smallest value of Young’s modulus was calculated for the Ti–Nb₂₂–Zr₆–Hf₅–Mg_2.5 alloy, achieving 57 GPa. Further increase in Mg concentration leads to a negative C′ and alloy destabilization. Additionally, alloying of the Ti–Nb₂₂–Zr₆ alloy results in a decrease in hardness, fracture toughness, but brittleness index is increased.

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