Method for preparing iron-based surface composite material by virtue of in-situ synthesis

Abstract

The invention relates to a metal-based composite material and specifically relates to a method for preparing an iron-based surface composite material by virtue of in-situ synthesis. The method disclosed by the invention comprises the following steps: uniformly mixing reactant Al and Fe2O3 (or Fe2O3 plus Cr2O3) powder, forming and pre-sintering to form particles, and then preparing a pre-formed body to ensure the penetration of molten iron or molten steel in the reactant pre-formed body, so that the flexible design of a composite layer is realized, the in-situ chemical reaction among reactants is initiated through the heating action of the molten iron, a high-hardness reinforcement phase is obtained, the molten iron at the higher temperature can be ensured by reaction heat release, and material densification can be realized by continuous infiltration of the molten iron or the molten steel into the reactant pre-formed body and among reaction products.

Description

technical field [0001] The invention relates to a metal-based composite material, in particular to a method for preparing an in-situ synthesized iron-based surface composite material. technical background [0002] Wear-resistant materials need to have high hardness and high toughness at the same time. Although the overall composite improves the strength, it greatly reduces the toughness, and wear usually only occurs on the specific surface of the part. In addition, the overall composite material is not conducive to recycling and reuse, resulting in material Waste and environmental pollution; therefore, material researchers have developed a surface composite material that generates a high-hardness wear-resistant layer on the surface of a tough substrate (such as steel), which has both good surface wear resistance and matrix toughness, It can meet the requirements of actual working conditions for surface or local wear resistance of parts; different working conditions have diff...

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Problems solved by technology

[0003] At present, the preparation of iron-based surface composites mainly focuses on the traditional method of adding particles, which has the following disadvantages: the compatibility between the added particles and the matrix is ​​not good, and surface pollution and attachments are inevitable, resulting in interface bonding with the matrix. Not strong; the sharp corners of the added particles have a splitting effect on the matrix, which may cause cracks and cause the material to break and fail. Therefore, its strengthening effect cannot be fully exerted; in the middle and late 1980s, material workers invented the in-situ self-generated composite method. Also known as the in-situ endogenous composite method, its salient features are: ①The reinforcement is a thermodynamically stable phase that grows from the in-situ nucleation inside the metal matrix, and is well combined with the matrix; ②By optimizing the design and process parameters, different sizes can be obtained. , the number of reinforcements, and their distribution can also be adjusted; ③ saves the process of separately synthesizing, processing, adding and dispersing reinforcements, simplifies the process, reduces equipment, and reduces costs; ④ uses the liquid in-situ reaction synthesis process, which can Casting to prepare parts with complex shapes; ⑤ The particle reinforcement phase synthesized in situ has no obvious sharp angles and the particle size is small; it overcomes various disadvantages of external particles, and has achieved rapid development in the current material preparation, and some products have been To achieve practicality, the specific methods are: high-energy beam surface in-situ cladding method, coating casting method (also known as reaction casting infiltration method), in-situ reaction spraying method, SHS (self-propagating high-temperature synthesis) casting technology, centrifugal self-propagating method Wait

[0006] A large number of studies have shown that the melt infiltration method is currently the most suitable composite process for preparing iron-based surface composite materials, but it is not the best process; from the existing research, due to the limitations of reinforcing materials and preparation processes, the surface composite The thickness of the layer is often not more than 10mm. In many cases, it is difficult to meet the requirements for the thickness of the wear-resistant layer. The composite material obtained by the reaction sintering method can obtain a good interface bond, and the thickness of the wear-resistant layer can be guaranteed, but there are usually The reaction process is difficult to control and the compactness of the composite material is low; therefore, it is necessary to research and develop a suitable new preparation process to prepare the iron-based composite material with controllable thickness, compactness and good wear resistance of the composite layer

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