次世代航空機用Ti-4.5%Al-2%Mo-1.6%V-0.5%Fe-0.3%Si-0.03%C合金のミクロ組織と機械的性質の関係

The effects of microstructures on the mechanical properties of Ti–4.5Al–2Mo–1.6V–0.5Fe–0.3Si–0.03C (KS Ti-9) were systematically investigated by conducting several heat treatments for next-generation aircraft applications. The mechanical strength of as-received KS Ti-9 exhibits high anisotropy that is derived from the intense texture (T-texture) of the primary α phase. Such high anisotropy is observed in KS Ti-9 annealed at temperatures slightly below β-transus, but it is drastically decreased in KS Ti-9 subjected to an anisotropy controlling treatment. The reduction in the anisotropy for KS Ti-9 is related to the differences in the orientations of the precipitated acicular α phase.