Ultra-fine gradient hard alloy with WC grains in surface rich binding-phase layer arrayed in regular shape and preparation method of ultra-fine gradient hard alloy

Abstract

The invention provides an ultra-fine gradient hard alloy with WC grains in a surface rich binding-phase layer arrayed in a regular shape and a preparation method of the ultra-fine gradient hard alloy,belongs to the field of hard alloy manufacturing, and particularly relates to an ultra-fine gradient hard alloy with WC grains in a surface rich binding-phase area arrayed regularly and distributed in an oriented mode and a preparation method of the ultra-fine gradient hard alloy. The surface of the gradient hard alloy is the rich binding-phase layer only containing WC and Co and having the thickness of 40-80 [mu]m, and the WC grains in a rich binding phase are approximately in a rectangular shape and are regularly arrayed and distributed in order; and WC, Co and a cubic phase are uniformly distributed in a core part, and the WC grains are distributed in an irregular and disordered shape. The preparation method comprises the steps that ingredients are ball-milled and then pressed into a hard alloy block, and the hard alloy block is sintered under pressure first and then sintered in a gradient manner under a vacuum nitrogen-free atmosphere to be subjected to heat treatment, so that theultra-fine gradient hard alloy with the WC grains in the surface rich binding-phase area distributed in the oriented mode is obtained. The ultra-fine gradient hard alloy is reasonable in structural design, the preparation process is controllable, the production cost is low, and the ultra-fine gradient hard alloy can be industrially produced and used to a large scale.

Description

Technical field [0001] The invention belongs to the field of cemented carbide manufacturing, and in particular relates to an ultra-fine-grain gradient cemented carbide with regularly arranged WC crystal grain shapes in a binder-rich phase layer on the surface and a preparation method thereof. Background technique [0002] Cemented carbide is a kind of refractory metal compound (WC, TiC, TaC, NbC, etc.) as the hard phase, transition group metals (Fe, Co, Ni) as the binder phase, prepared by powder sintering method Alloy materials have the advantages of higher strength, hardness, and better wear resistance. They are mainly used to make tools or molds, and are widely used in cutting and mold manufacturing. In recent years, with the development of material science and machining industry, the wear resistance, strength, hardness and resistance to plastic deformation of cemented carbide materials under high-speed and high-temperature continuous working conditions have become increasingl...

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Problems solved by technology

[0009] The purpose of the present invention is to solve the problem that the grain size of the gradient structure cemented carbide has large grain size, low strength and hardness, and high toughness in the hard layer under the rich binder phase gradient layer. The deformability is poor, the two-stage sintering process adopted is complicated, and it is difficult to control the deficiencies

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