Non-homogeneous gradient hard alloy and preparation method thereof

Abstract

The invention discloses non-homogeneous gradient hard alloy and a preparation method thereof. According to the non-homogeneous gradient hard alloy, Co serves as a binding phase, a tungsten carbide and titanium-containing cubic phase compound serves as a hard phase, the titanium-containing cubic phase compound accounts for 2-8 wt.% of the mass fraction of the non-homogeneous gradient hard alloy, tungsten carbide grain distribution has a double-peak structure, the original particle size is rough and fine, and the non-homogeneous gradient hard alloy is of a surface structure without a titanium-containing cubic phase compound with the average binding phase content 1-2 times of a nominal binding phase content. The preparation method includes the steps of material preparation, mixing, milling, compression molding and sintering. The non-homogeneous gradient hard alloy has higher hardness, toughness and bending strength and can meet the machining requirement of cast iron, alloy steel, stainless steel and other metal materials, the preparation method is simple in process, and cost is low.

Description

technical field [0001] The invention belongs to the field of powder metallurgy, and relates to a non-uniform gradient cemented carbide and a preparation method thereof, in particular to a cemented carbide with a non-uniform WC particle size distribution and a cubic phase gradient structure on the surface and a preparation method thereof. Background technique [0002] Surface lack of cubic phase (also known as de-β layer) gradient structure cemented carbide refers to adding a certain amount of cubic phase to the raw material powder, such as TiC, TiN or solid solution carbide (Ti, W) C, (Ta, Nb) C Or solid solution carbonitride (Ti, W) (C, N), (Ti, Ta, Nb) (C, N), TiCN, etc., the raw material powder is ball milled and mixed, and pressed into a green compact containing a cubic phase as a whole, after sintering In the stage, by changing the atmosphere in the furnace, a gradient layer of lacking cubic phase is formed on the surface of the substrate with a certain thickness. There...

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Problems solved by technology

However, non-uniform gradient cemented carbide cannot be realized by simply combining the two existing technologies of non-uniform alloy and gradient cemented carbide. On the one hand, the existing non-uniform gradient cemented carbide is mainly used for mining tools, milling tools, etc. In the field of metal turning, which requires high wear resistance and high temperature plastic deformation resistance, this structure obviously has the disadvantage of insufficient wear resistance. It is also difficult to realize the bimodal particle size distribution of WC grains in the process, because the fine WC powder is preferentially dissolved and precipitated during the sintering process, especially after the high cubic phase compound is added, WC will dissolve into it, so the fine WC Solubility will increase further, making it difficult to control fine WC particle size and ratio

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