Tungsten carbide-intermetallic compound hard alloy of twin structure and preparation method thereof

Abstract

The invention provides a tungsten carbide-intermetallic compound hard alloy of a twin structure. The alloy comprises a hard phase WC and an adhesive phase Ni3Al or FeAl or Fe3Al, wherein the adhesive phase is 10 to 40 volume percent. A manufacturing method for the alloy sequentially comprises the following steps of: mixing Ni powder or Fe powder, Al powder and fine WC powder uniformly according to the component proportion of the Ni3Al or the FeAl or the Fe3Al; spreading the mixed powder in a graphite container, heating the mixed powder to the temperature of between 900 and 1,200 DEG C under a non-oxidizing atmosphere, preserving the heat for over 1 hour, naturally cooling the heated powder, and coating the adhesive phase to the surface of the fine WC; grinding, crushing and screening the mixture of the fine WC and the adhesive phase; performing deoxidation pretreatment at the temperature of 400+ / -50 DEG C under the hydrogen atmosphere; performing pre-wet milling on 52.31 to 75.97 weight percent or 55.79 to 76.97 weight percent or 53.66 to 76.37 weight percent of crude granular WC powder and the balance of mixed powder to obtain a wet milled mixture; performing spray drying and pressure molding; and performing low-pressure liquid phase sintering at the temperature of between 1,250 and 1,550 DEG C, and thus obtaining the tungsten carbide-intermetallic compound hard alloy of the twin structure. The crude crystal WC and the fine crystal WC are matched uniformly, so the alloy has high densification, high strength, good abrasion resistance and excellent high-temperature oxidation resistance and corrosion resistance; and the preparation method is simple and low in cost.

Description

technical field [0001] The invention relates to a cemented carbide material and a preparation method thereof, in particular to a twin-crystal structure material with tungsten carbide as a matrix and an intermetallic compound as a binding phase prepared by powder metallurgy technology and a preparation method thereof. Background technique [0002] The composition of WC-based cemented carbide is mainly composed of high-hardness hard phase WC and plastic-tough binder phase Co, Ni, and Fe metals. Among them, the plastic and tough metal binder phase is mainly used as the second phase to improve its toughness. Therefore, the characteristics of the binder phase have a great influence on the performance of the material. However, Co, Ni, and Fe binder phases are difficult to adapt to harsh working environments such as acidity and high temperature oxidation, thus limiting the industrial application range of cemented carbide. Compared with ordinary Co, Ni, Fe binder phase metals, int...

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Problems solved by technology

However, due to the absence of the ball milling process, the activity of the powder is very low, and the alloy is not easy to achieve full densification during the sintering process.

The two coating methods both use chemical solvents, which are likely to have adverse effects on the environment during the preparation process

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