Method for preparing gradient nano-structure on surface of metal material

Abstract

The invention relates to a method for preparing a gradient nano-structure on the surface of a metal material. According to the method, a processed plate workpiece is placed inside a cooling tank; a fixture is adopted to tightly press the workpiece; the lower end surface of a tool head is placed on the surface of the workpiece, and is pressed into the surface of the workpiece; a cooling medium is poured into the cooling tank, wherein the workpiece is submerged by the cooling medium; after a temperature of the workpiece reaches a temperature of the cooling medium, the tool head rotates at a certain speed while a work table horizontally moves at a certain speed to drive the workpiece to horizontally move at a certain speed so as to complete a shear deformation treatment by the high hardness end surface of the tool head during a high speed rotation process, wherein high strain rate and large strain are generated to the surface of the workpiece with the shear deformation treatment, and a plurality of deformation treatments are performed on the surface of the workpiece by using the high-speed shear deformation technology. Compared with the method in the prior art, the method of the present invention has advantages of high processing efficiency, low equipment loss, low manufacturing cost, simple process, strong applicability, and the like.

Description

technical field [0001] The invention relates to a method for forming nanometerization on the surface of a metal material, in particular to a method for preparing a gradient nanostructure on the surface of a metal material. Background technique [0002] Nanocrystalline materials are currently an extremely active research hotspot in the field of materials science and engineering. Their excellent mechanical properties and unique physical and chemical properties have attracted widespread attention worldwide; in recent years, the surface nanoscale of metal materials has gradually It has become a research hotspot, because the failure of metal materials mostly occurs on the surface of the material, and the structural properties of the surface directly affect the comprehensive service performance of engineering metal materials. A nanostructured surface layer with a certain thickness (below 100 μm) is prepared on the surface of the material, that is, the realization of surface nanostr...

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Problems solved by technology

Although this method refines the surface structure to a certain extent, it is very difficult to achieve a complete nanoscale (below 100nm) at room temperature, and it is even impossible for aluminum with high stacking fault energy; Chinese invention patent "metal surface The method in "Nanoization Method" (publication number CN101012493A, publication date August 8, 2007) uses a cylindrical tool with a flat end surface to rotate and press into the surface of the material. This method also has the above-mentioned difficulty in nanotechnology; China Invention patent "A method and equipment for preparing large-thickness and large-area nanomaterials by severe plastic deformation" (publication number CN101544352A, publication date September 30, 2009), using electromagnetic coupling and low-temperature cooling to prepare large-thickness nanostructures Layer, not only the equipment structure is complicated, but also its practicability is very limited. Although the method uses a low-temperature cooling stirring head to cool the metal in the processing area, it is difficult to dissipate all the heat generated by the stirring friction through the stirring head, and then It affects the formation of metal nanocrystals in the processing area; there is also a method of surface mechanical grinding for surface nanocrystallization (Chinese Invention Patent Publication No.: CN1301873A, CN1336444, CN1336321A, CN1336445A), and the deformation method is surface compression caused by shot peening Deformation, not only the equipment is relatively complicated, but also cannot be processed in a large area; the Chinese invention patent "High-speed processing method for realizing ultra-fine grain structure on the surface of metal materials" (public number CN101323900A) proposes a mechanical processing method through high-speed plastic deformation of the surface , so that the surface of the metal material forms an ultra-fine structure. This method is characterized by high-speed rotation of the workpiece, but the processing tool does not rotate. This method is only suitable for ultra-fine processing of the surface of the rotary part, and cannot be used for large-area plane processing. Not only The deformation rate of the surface metal is limited by the rotational speed of the workpiece, and the processing efficiency is low

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