Electrochemical corrosive agent for precipitation strengthening phase of high-temperature alloy and application method of electrochemical corrosive agent

Abstract

The invention discloses an electrochemical corrosive agent for a precipitation strengthening phase of a high-temperature alloy and an application method of the electrochemical corrosive agent. The electrochemical corrosive agent is prepared from the following raw materials in proportion: 50-60ml of phosphoric acid solution, 40-50g of oxalic acid solid powder, 25-40ml of glycerol, 2-4g of copper chloride solid powder and 150-175 ml of deionized water, wherein a surface cleaning agent is formed by 20-30 ml of absolute ethyl alcohol solution and 20-30 ml of deionized water; and by combining the overall structure recrystallization homogenization degree under different heat treatment systems and different electrochemical corrosion transpassivity dissolution characteristics of each precipitationstrengthening phase under different component contents, a method of controlling corrosion parameters step by step is adopted, and clear and accurate precipitation strengthening phases under differentheat treatment systems can be obtained. The electrochemical corrosive agent provided by the invention is convenient to prepare, not only solves the problem of poor cold chemical corrosion effect, butalso avoids the difficulty in controlling thermochemical corrosion, and realizes high-efficiency corrosion on the premise of ensuring the corrosion quality.

Description

technical field [0001] The invention relates to the field of phase detection and analysis in high-temperature alloys, in particular to an electrochemical corrosion agent for precipitation strengthening phases of high-temperature alloys and a use method thereof. Background technique [0002] IN 718 nickel-based alloy is the main representative of precipitation-hardening superalloys. Firstly, metal elements (such as Cr, Fe, Co, Mo) with similar atomic radius to Ni matrix elements form an infinite solid-solution matrix γ phase to exert the "solid-solution "Strengthening" effect, and the second strengthening phase characteristics precipitated by the matrix γ phase in the intragranular and intergranular during the subsequent heat treatment (including: the main strengthening phase γ" phase-Ni with a body-centered tetragonal structure 3 Nb, an auxiliary strengthening phase with a face-centered cubic structure γ' phase-Ni 3 (Al, Ti, Nb) and δ phase-Ni with orthorhombic structure 3...

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Problems solved by technology

[0004] However, in the research and analysis of the heat treatment microstructure of the SLM formed IN 718 material, on the one hand, due to the dissolution of the Laves phase after heat treatment, the material contains a large amount of Ni and Cr solid solution elements, which will cause the material to be damaged due to the formation of the formed part after heat treatment. A large amount of the above-mentioned Ni and Cr elements are gathered to cause adsorption and oxidation reactions, and the surface is covered with a thick and dense oxide film to have strong corrosion resistance. Even if the current mainstream mixed strong corrosive method is used for cold chemical corrosion (such as patent CN 105780005 B, the technology disclosed in patent CN 105002498 A) is also difficult to break the oxide film to obtain clear and accurate metallography; and further research mainly focuses on the above-mentioned environment of cold chemical corrosives for heating in a water bath to form thermochemical corrosion (As the disclosed technology of patent CN 1465745), due to the difficult control of water bath temperature and water bath time, it is difficult to control the corrosion depth of precipitated phase and crystal; on the other hand, due to different heat treatment systems (such as aging treatment, solid solution treatment, high temperature homogenization treatment, etc.) will determine different degrees of recrystallization process, the solubility of Laves phase and the precipitation of the second strengthening phase, and if complete recrystallization does not occur, there will still be mixed with original The crystal structure of the state, then the electrochemical corrosion of the process of combining the crystal structure characteristics of the material with different electrochemical dissolution characteristics under the action of different power parameters can be used as a more effective control method

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