Preparing method for powder metallurgy high-entropy alloy based composite material

Abstract

The invention relates to a preparing method for a powder metallurgy high-entropy alloy based composite material, and belongs to the field of powder metallurgy materials. The preparing method includes the steps that all components are prepared and taken according to component proportions of a designed high-entropy alloy matrix, and high-entropy alloy powder is prepared through a gas atomization method; and then according to the component proportions of the designed high-entropy alloy based composite material, the high-entropy alloy powder and wild phase titanium diboride powder are prepared and taken, and rapid sintering molding is achieved after even mixing is carried out. According to the preparing method, the atomization method is adopted for preparing spherical high-entropy alloy powder with relatively-even ingredients in advance, and therefore a simple solid solution phase structure of a high-entropy alloy is guaranteed; and discharging plasma rapid sintering is adopted for preparing the needed powder metallurgy high-entropy alloy based composite material, and therefore the shortcoming that the material is prepared with metal powder as a raw material through a powder metallurgy method traditionally, and consequently the high-entropy alloy of the simple solid solution structure is difficult to obtain is overcome. The preparing method is simple in process procedure; according to the prepared powder metallurgy high-entropy alloy based composite material, titanium diboride is evenly distributed, reinforcement and base body interface bonding is better, the comprehensive performance is more excellent, the specific strength is high, the specific rigidity is high, and the abrasive resistance and the corrosion resistance are excellent. The preparing method is suitable for industrial production.

Description

technical field [0001] The invention relates to a method for preparing a powder metallurgy high-entropy alloy-based composite material. The invention belongs to the technical field of powder metallurgy material preparation. Background technique [0002] High-entropy alloys use five or more metals as the main elements, and the mole fraction of each element is between 5% and 35%. It has a simple solid solution phase structure, such as a face-centered cubic (FCC) phase, disordered Body-centered cubic (BCC) phase, ordered body-centered cubic (B2) phase or hexagonal close-packed (HCP) phase. Due to the characteristics of high entropy alloys such as high entropy, large lattice distortion, slow diffusion and Cocktail effect, the alloy presents a simple solid solution phase structure on the microstructure, and its performance is high strength / hardness and work hardening, high temperature resistance Oxidation and softening, good wear resistance and corrosion resistance, and its com...

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Problems solved by technology

[0003] Chinese patent (application number: 200810063807.4, 2008) developed a TiB 2 The high-entropy alloy-based composite material is a reinforcing phase, and its preparation methods include arc melting, induction melting, self-propagating-melting casting or powder metallurgy manufacturing, among which three methods such as electric arc melting, induction melting, and self-propagating-melting casting are uniform It is to melt the matrix material of the high-entropy alloy into a liquid, and then add the reinforcement phase to the melt to stir and cast it. These methods generally have the uneven composition of the high-entropy alloy matrix in the composite material and serious branching. Grain segregation, while the reinforcements appear to agglomerate and distribute unevenly, and at the same time, different degrees of reactions will occur between the matrix phase and the reinforcement, resulting in harmful phases at the interface between the matrix and the reinforcement of the composite material, reducing the strength of the composite material. ; and adopt powder metallurgy process to prepare high entropy alloy matrix composite material, this method is: (1) put TiB 2 Reinforcing phase and Al, Cu, Ni, Co, Ti and other metals that make up the high-entropy alloy are weighed in proportion to the powder raw materials of each element, sealed and mixed evenly, then pressed into blocks, and then cold-pressed into prefabricated blocks; (2) cold-pressed prefabricated The block is dried and degassed, then put into a graphite mold for hot pressing and sintering for 2 hours, and then cooled in a furnace to obtain a composite material

This method uses the raw materials of metal powders of each element that make up the high-entropy alloy and the reinforcement TiB 2 Mixed hot pressing sintering, the preparation process is relatively long, it is difficult to ensure that the matrix of the composite material is a high-purity high-entropy alloy, and because the melting point and activity of each metal element that constitutes the high-entropy alloy are different, during the long-term high-temperature sintering process, TiB 2 The metal elements of the reinforcement and the matrix will react to different degrees, and it is difficult to control the phase composition of the composite material

[0004] At present, there is no spherical high-entropy alloy powder prepared by atomization method as the matrix phase raw material, and titanium diboride-reinforced powder metallurgy high-entropy alloy matrix composites are prepared by spark plasma sintering

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