Hard alloy added with boron element and preparation method thereof

Abstract

The invention provides a boron-doped hard alloy and a preparation method thereof. The mass percentage of boron element to bonder is 0.01 percent to 2 percent, preferably 0.05 percent to 1 percent. The preparation method comprises compounding, ball milling, drying, pressing and sintering steps. The boron exists in the form of pure boron powder, TiB2, CrB2, WB, CoB or a combination thereof. During the compounding step, the boron element is mixed thoroughly with WC and Co, and the resulting mixture is subjected to ball mill for 24-72 hours in the presence of alcohol. The strength and hardness of hard alloy are increased while the toughness remains unchanged, or the strength, hardness and toughness all increased.

Description

technical field [0001] The invention relates to a hard alloy and a preparation method thereof, in particular to a hard alloy added with boron element and a preparation method thereof. Background technique [0002] The strength and hardness of cemented carbide are a pair of contradictory properties. Generally speaking, the harder the material is, the more brittle it is, and the strength is relatively low. Usually, a balance between strength and hardness is required in applications. For this reason, it was proposed to improve the performance of cemented carbide by adding boron (B). There are two main ways to add boron to cemented carbide: one is to add boron oxide or carbide powder to the raw material powder mixture at the beginning of alloy production, such as B in Japanese patent JP2005068479 2 o 3 As the main addition form of boron; use the chemical stability of boron oxides or carbides to avoid other side reactions that lead to alloy performance degradation in the subseq...

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Problems solved by technology

There are two main ways to add boron to cemented carbide: one is to add boron oxide or carbide powder to the raw material powder mixture at the beginning of alloy production, such as B in Japanese patent JP2005068479 2 o 3 As the main addition form of boron; use the chemical stability of boron oxides or carbides to avoid other side reactions that lead to alloy performance degradation in the subsequent alloy manufacturing process, but it is not conducive to the diffusion and uniform distribution of boron elements; The first is to coat (or surround) the compact or the product with boron-containing materials during the sintering process of the compact in alloy production, or on the sintered alloy product, and pass a certain amount of boron through it in the sintering atmosphere. It is transferred to the molding material by thermodynamic action, and diffuses from the surface of the molding material to the entire microstructure at a depth of at least 3mm, thereby realizing the addition of boron, such as Liu Shourong, Song Junting, etc. in "WC-Co cemented carbide sintering process infiltration High-temperature dynamic phase analysis of boron" (Carbide, 2002, 19 (1)), Liu Shourong, Hao Jianmin, etc. in "WC-Co cemented carbide sintering process yttrium-boron co-infiltration mechanism" (Rare Metal Materials and Engineering, 2003, 32(4)) and other documents; but this method is not easy to control the degree of reaction

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