A kind of electrochemical corrosion agent for precipitation strengthening phase of superalloy and using method thereof

Abstract

The invention discloses an electrochemical etchant for precipitation strengthening phase of superalloy and its use method. The electrochemical etchant comprises the following raw materials: the electrochemical etchant consists of phosphoric acid solution 50-60ml, oxalic acid solid powder 40-50g, glycerin 25 ~ 40ml, copper chloride solid powder 2 ~ 4g, deionized water 150 ~ 175ml; surface cleaning agent is composed of 20 ~ 30ml of absolute ethanol solution and 20 ~ 30ml of deionized water, combined with different heat treatment systems The degree of homogeneity of the overall recrystallization of the structure and the different electrochemical corrosion and overpassivation dissolution characteristics of each precipitation strengthening phase at different component contents can be obtained clearly and accurately under different heat treatment systems by using the method of step-by-step control of corrosion parameters. The structure of the precipitation strengthening phase, the electrochemical etchant of the present invention is convenient to configure, not only solves the problem of poor cold chemical corrosion effect, but also avoids the difficult control of thermal chemical corrosion, and realizes efficient corrosion under the premise of corrosion quality assurance.

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...

AI Technical Summary

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

Images