The invention discloses a
rare earth modified cast high-temperature
titanium alloy and a preparation method and application thereof, and belongs to the technical field of high-temperature
titanium alloys. The
alloy comprises the following components in percentage by
mass: 5.50% to 6.50% of Al, 3.50% to 5.00% of Sn, 3.50% to 5.00% of Zr, 0.20% to 0.80% of Mo, 0.10% to 0.30% of Si, 0.25% to 0.55% of Nb, 0.20% to 0.40% of Ta, 0.40% to 0.60% of W, 0.25% to 0.35% of Nd and the balance of Ti and impurities. By adding narrow-interval
rare earth Nd and utilizing the synergistic effect of structure purification and dispersion strengthening, the effective Al equivalent of an alpha phase is reduced, so that
precipitation and growth of a Ti3Al brittle ordered phase in the high-temperature long-time
service process are remarkably inhibited. The preparation method comprises a vacuum melting process and an innovative five-stage
hot isostatic pressing process, and the process realizes densification, homogenization and structure stabilization integrated treatment through programmed
temperature and pressure regulation and control. The obtained
alloy has excellent high-temperature strength,
plasticity and long-
time structure stability at the temperature of 650 DEG C or above, and is suitable for high-temperature structural parts of aero-engines and
gas turbines.