High-temperature-stability gamma'-phase-reinforced cobalt-base high-temperature alloy and preparation method thereof

Abstract

The invention belongs to the technical field of new materials, and relates to a gamma'-phase high-temperature-stability cobalt-base high-temperature alloy with gamma / gamma' two-phase structure, which is a candidate material for high-temperature hot end components of gas turbines for aviation, spaceflight, vessels, power generation and the like. The alloy comprises the following components in atomic percentage: 4-12% of Al, 4-12% of W, 1-4% of Ta, 1-6% of Ti, 0-10% of Cr, 0-3% of Mo, 0-2% of Hf, 0-1% of C, 0-1% of B and the balance of Co. The preparation method comprises the following steps: smelting in a vacuum induction furnace, carrying out solid solution heat treatment at 1250-1300 DEG C, and carrying out aging heat treatment at 1000-1100 DEG C. After carrying out L12-type gamma'-phase high-temperature reinforcement, the gamma' shape is cubic, the volume percent is higher than 60%, and the gamma'-phase is uniformly distributed in the gamma-phase. Compared with the traditional cobalt-base high-temperature alloy, the alloy provided by the invention has higher application temperature; and compared with the recently developed similar cobalt-base alloys, the alloy provided by the invention has higher gamma'-phase solution temperature and gamma / gamma' two-phase structure stable existence temperature.

Description

technical field [0001] The invention belongs to the technical field of new materials, and relates to a cobalt-based superalloy having a gamma / gamma' two-phase structure and a gamma' phase stable at high temperature. Background technique [0002] Superalloys are widely used in aerospace, marine ships, energy power, nuclear industry, petrochemical and other fields, especially for hot end components of advanced power propulsion systems such as turbine engines. Such parts mostly use nickel-based superalloys, because they not only have excellent oxidation and corrosion resistance, but also have L1 2 Excellent high-temperature mechanical properties provided by the γ' phase strengthening of the crystal structure. [0003] Cobalt-based superalloys are an earlier class of superalloys, which have a higher melting point than nickel-based alloys, superior hot corrosion resistance, thermal fatigue resistance and welding performance. However, because it mainly relies on solid solution ...

AI Technical Summary

Problems solved by technology

[0005] However, the main problem of existing Co-Al-W-based alloys is that the γ' phase dissolution temperature is mostly in the range of 1000 ~ 1100°C, resulting in a γ / γ' two-phase structure with a typical strengthening effect (the volume fraction of the γ' phase is greater than 60%, and evenly distributed in the γ phase) the formation temperature range is only 900 ~ 1000°C, it is not easy to form a similar γ / γ' two-phase structure in a higher temperature range above 1000°C, so that it cannot further increase its high temperature Strength, indicating that the temperature bearing capacity of such cobalt-based alloys is still limited

Images