A precipitation-strengthened nickel-cobalt-based alloy with high oxidation resistance and its preparation method

Abstract

The invention discloses a precipitation-strengthened nickel-cobalt-based alloy with high oxidation resistance and a preparation method thereof. The composition of the alloy is calculated by weight percentage: 0.03≤C≤0.1%, 0<B≤0.003%, 14≤Cr≤ 17%, 25≤Co≤30%, 3≤W≤12%, 0.5≤Nb≤2%, 2.5≤Al≤6%, 1≤Ti≤4%, 0≤Hf≤0.15%, 0≤Ta≤2 %, the balance is Ni, wherein, when 1.5≤Al / Ti<3, 4<Cr / Al≤6; when 3≤Al / Ti≤6, 2.5≤Cr / Al≤4. When the Al content is constant, the Al / Ti ratio in the alloy is used to reduce the Cr content and promote the alloy to spontaneously form a protective Al 2 o 3 The film solves the technical problem that the alloy must simply increase the content of Cr or Al to improve the oxidation resistance, and increases the adjustment margin of the content of other elements in the alloy.

Description

technical field [0001] The invention relates to the field of nickel-cobalt-based alloys, in particular to a precipitation-strengthened nickel-cobalt-based alloy with high oxidation resistance and a preparation method thereof. Background technique [0002] Due to its excellent high-temperature strength, fatigue performance and good high-temperature oxidation / corrosion resistance, superalloys based on iron, cobalt, and nickel can work in high-temperature environments above 600°C for a long time. Among the three types of superalloys, traditional cobalt-based superalloys mainly rely on solid solution strengthening or carbide strengthening, and their high-temperature strength is low, so they are mainly used in environments with low mechanical loads. In contrast, nickel-based superalloys with γ′ (Ni 3 Al) phase strengthening is the main strengthening method, which has excellent mechanical properties, but the corrosion resistance of nickel-based superalloys is poor. In order to a...

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Problems solved by technology

Among the three types of superalloys, traditional cobalt-based superalloys mainly rely on solid solution strengthening or carbide strengthening, and their high-temperature strength is low, so they are mainly used in environments with low mechanical loads.

However, the increase of Cr content will inevitably lead to the increase of α-Cr phase precipitation tendency in the alloy, making the material brittle; while the increase of Al content will reduce the plasticity, hot workability and welding performance of the alloy

At the same time, when the Ti content is high, the alloy is more likely to form TiO at high temperature, especially in the high temperature environment containing water vapor. 2 , which weakens the oxidation resistance of the alloy

This means that in the design of superalloys, improving the oxidation resistance of the alloy is contradictory to improving the mechanical properties of the alloy, and it is difficult to improve the oxidation resistance and mechanical properties of the alloy at the same time

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