阅读说明：本技术 一种聚晶复合材料 (Polycrystalline composite material ) 是由 孔帅斐 李和鑫 李麟 李翠 于 2020-04-13 设计创作，主要内容包括：本发明属于超硬材料技术领域,具体涉及一种聚晶复合材料。本发明的聚晶复合材料由由超硬材料、金属复合结合剂制成；所述超硬材料为立方氮化硼；所述金属复合结合剂包括金属和钛铝铬氮纳米粉体。本发明的聚晶复合材料中,采用金属以及钛铝铬氮纳米粉体共同作为结合剂,钛铝铬氮纳米粉体能够促进金属的晶粒细化,实现固溶强化和析出强化,从而使得聚晶复合材料的耐磨性得到有效提高。(The invention belongs to the technical field of superhard materials, and particularly relates to a polycrystalline composite material. The polycrystalline composite material is prepared from a superhard material and a metal composite binding agent; the superhard material is cubic boron nitride; the metal composite bonding agent comprises metal and titanium-aluminum-chromium-nitrogen nano powder. In the polycrystalline composite material, the metal and the titanium-aluminum-chromium-nitrogen nano powder are used as a binding agent, and the titanium-aluminum-chromium-nitrogen nano powder can promote grain refinement of the metal and realize solid solution strengthening and precipitation strengthening, so that the wear resistance of the polycrystalline composite material is effectively improved.)

1. A polycrystalline composite material is characterized by being prepared from a superhard material and a metal composite binder; the superhard material is cubic boron nitride; the metal composite bonding agent comprises metal and titanium-aluminum-chromium-nitrogen nano powder.

2. The polycrystalline composite material according to claim 1, wherein the titanium-aluminum-chromium-nitrogen nanopowder has an atomic ratio of titanium to aluminum to chromium to nitrogen of 1: (0.2-0.5): (0.2-0.3): (0.9-1.2).

3. The polycrystalline composite material according to claim 1 or 2, wherein the titanium-chromium-aluminum-nitrogen nanopowder is synthesized by a direct current arc plasma method, and during synthesis, titanium-aluminum-chromium alloy is used as an anode target material, and argon, hydrogen and nitrogen are used as plasma working gases.

4. The polycrystalline composite material according to claim 3, wherein the current used in the synthesis of the titanium chromium aluminum nitrogen nanopowder by the direct current arc plasma method is 90-120A.

5. The polycrystalline composite material according to claim 3, wherein the volume ratio of the argon gas to the hydrogen gas to the nitrogen gas is (10-15): (1-5): (8-12).

6. The polycrystalline composite material according to claim 1 or 2, wherein the mass of the titanium-aluminum-chromium-nitrogen nanopowder is 5-10% of the total mass of the superhard material and the metal in the metal composite binder.

7. The polycrystalline composite material according to claim 1 or 2, wherein the mass ratio of the superhard material to the metal in the metal composite binder is (7-9): (3-1).

8. The polycrystalline composite material according to claim 1 or 2, wherein the metal is at least two of titanium, aluminum, cobalt, chromium, niobium.

9. The polycrystalline composite material according to claim 1 or 2, wherein the polycrystalline composite material is a friction stir welding tool, a polycrystalline cubic boron nitride compact.

Technical Field

The invention belongs to the technical field of superhard materials, and particularly relates to a polycrystalline composite material.

Background

Polycrystalline diamond (PCD) and Polycrystalline Cubic Boron Nitride (PCBN) have excellent properties such as high hardness and wear resistance, high stability, and high temperature hardness, and thus are widely used in the technical fields of cutting tools, welding, and the like. Because diamond particles and cubic boron nitride particles have the defect of being difficult to sinter, most of PCD and PCBN are polycrystalline composite materials formed by sintering diamond, cubic boron nitride and a binding agent. The bonding agent commonly used in the prior art is a metal bonding agent, but the metal bonding agent is easy to soften or even melt at a higher temperature, so that the wear resistance of PCD and PCBN, especially the high-temperature wear resistance, is reduced, and the use of the PCD and PCBN is influenced.

Disclosure of Invention

The invention aims to provide a polycrystalline composite material which has better wear resistance.

In order to achieve the purpose, the invention adopts the technical scheme that:

a polycrystalline composite material is prepared from a superhard material and a metal composite binder; the superhard material is cubic boron nitride; the metal composite bonding agent comprises metal and titanium-aluminum-chromium-nitrogen nano powder.

In the polycrystalline composite material, metal and titanium-aluminum-chromium-nitrogen nano powder are used as a binding agent, and the titanium-aluminum-chromium-nitrogen nano powder can promote the refinement of metal grains in the metal binding agent and realize solid solution strengthening and precipitation strengthening, so that the wear resistance of the polycrystalline composite material is effectively improved. When the fine grain metal is acted by external force, plastic deformation occurs, the fine grain metal can be dispersed in more grains, the plastic deformation is uniform, the stress concentration is less, and the small grain boundary area and the large grain boundary tortuosity of grains are not beneficial to crack propagation. Meanwhile, the titanium-aluminum-chromium-nitrogen nano powder has fine granularity, and CrN, AlN and other fine particles are separated out and dispersed in the material at a high temperature, so that the effect of dispersion strengthening is achieved.

Preferably, the atomic ratio of titanium, aluminum, chromium and nitrogen in the titanium-aluminum-chromium-nitrogen nano powder is 1: (0.2-0.5): (0.2-0.3): (0.9-1.2). The titanium aluminum chromium nitrogen nano powder has the structure that excessive aluminum and chromium elements are introduced into titanium nitride, so that the lattice of titanium nitride crystals is enlarged, and aluminum and chromium enter gaps of the titanium nitride crystals.

The size of the nano material (with the size of 1-100 nm) is close to the coherence length of electrons, the particle size is small, the specific surface area is large, and compared with a macroscopic material, the nano material has the characteristics of excellent surface effect, small size effect, quantum size effect, macroscopic quantum tunneling effect and the like. The titanium-aluminum-chromium-nitrogen composite material is formed by the titanium-aluminum-chromium-nitrogen composite material and the superhard material in the form of nano powder, and the performance of the polymeric composite material is effectively improved by utilizing the size effect of the titanium-aluminum-chromium-nitrogen composite material.

Preferably, the titanium-aluminum-chromium-nitrogen nano powder is synthesized by a direct current arc plasma method, and during synthesis, titanium-aluminum-chromium alloy is used as an anode target material, and argon, hydrogen and nitrogen are used as plasma working gases. The principle of the nano powder prepared by the direct current arc plasma method is that under a certain atmosphere and pressure, the cathode continuously performs arc discharge to generate high temperature, the molten anode target material is forced to evaporate, and a series of physical and chemical reaction processes are performed to generate a corresponding product. The method has the advantages that the prepared nano powder has uniform size and small particle size.

The particle size of the titanium-aluminum-chromium-nitrogen nano powder is optimized by adjusting specific process parameters of a direct current arc plasma method, and preferably, the current used when the titanium-chromium-aluminum-nitrogen nano powder is synthesized by the direct current arc plasma method is 90-120A. Preferably, the volume ratio of the argon to the hydrogen to the nitrogen is (10-15): (1-5): (8-12).

The performance of the polycrystalline composite material is optimized by adjusting the mass of the titanium-aluminum-chromium-nitrogen nano powder, preferably, the mass of the titanium-aluminum-chromium-nitrogen nano powder is 5-10% of the total mass of the superhard material and the metal in the metal composite binder.

Preferably, the mass ratio of the superhard material to the metal in the metal composite bonding agent is (7-9): (3-1). Preferably, the superhard material used has a median particle size of 50 μm and the metal has a median particle size of 0.5 μm.

The metal used in the metal composite binder is a metal binder commonly used in the prior art, and preferably, the metal is at least two of titanium, aluminum, cobalt, chromium and niobium.

The polycrystalline composite material can be prepared into a required form according to actual conditions, such as a polycrystalline composite sheet formed by compounding the polycrystalline composite material with a hard alloy matrix. Preferably, the polycrystalline composite material is a stirring head for friction stir welding and a polycrystalline cubic boron nitride composite sheet.

The polycrystalline composite material is prepared from a superhard material and a metal composite binding agent, and specifically comprises the following components in percentage by weight: the super-hard material, the metal bond and the titanium-aluminum-chromium-nitrogen nano powder are mixed, pressed, molded and sintered to prepare the titanium-aluminum-chromium-nitrogen nano powder. Wherein the pressing molding is cold pressing molding, and the pressure is 450-500 MPa. The pressure during sintering is 4.5-7 GPa, and the temperature is 1300-1800 ℃.

Drawings

FIG. 1 is a front view of a friction stir welding tool according to example 1 of the present invention;

FIG. 2 is a plan view of a friction stir welding tool according to example 1 of the present invention;

reference numerals: 1-stirring pin and 2-stirring head.

Detailed Description

The present invention will be described with reference to examples.