Method for preparing cubic boron nitride glomerocryst composite combined with high-entropy alloy

Abstract

Provided is a method for preparing a cubic boron nitride glomerocryst composite combined with high-entropy alloy. The method mainly comprises the steps that 40% to 95% of cubic boron nitride single crystals and 5% to 60% of high-entropy alloy binding agent by mass are evenly mixed and contained in a mold, the mixture is subjected to cold pressing on a hydraulic machine to be prepared into compact, and the pressure ranges from 30 MPa to 50 MPa and is kept for 2 min; the obtained compact is contained in a carbon tube furnace and assembled with a pressure transmitting medium, an assembled block is formed and placed between top anvils of a high-pressure press, the pressure ranges from 4 GPa to 6 GPa, the assembled block is heated to 1,200 DEG C to 1,650 DEG C, and the temperature is kept for 2 min to 25 min; then the pressure is removed, the assembled block is cooled to 60 DEG C or below, and the assembled block is taken out to obtain cubic boron nitride glomerocryst. No elementary element exists in the glomerocryst, a soft spot is avoided, and the hardness is relatively high and uniform; the sintering temperature and the expansion coefficient are controllable, the sintering temperature is reduced, sintering is easy, the toughness of the glomerocryst is improved, and heat stability is improved.

Description

technical field [0001] The invention belongs to the field of materials, in particular to a method for preparing cubic boron nitride polycrystals. Background technique [0002] PcBN (Polycrystalline Cubic Boron Nitride, Polycrystalline Cubic Boron Nitride, referred to as Polycrystalline Cubic Boron Nitride) is prepared by bonding tiny single crystal particles of cubic boron nitride (cBN) under high temperature and high pressure (1350-1650°C, 4-6.5GPa) to form a block. PcBN) is used to make tool materials for processing hardened steel, chilled cast iron, ultra-high-strength iron group alloys, titanium alloys and other difficult-to-machine metals. The binder that plays a bonding role accounts for 5-60% of the mass ratio, which will seriously affect the overall performance of PcBN. The most important indicators of tool materials are hardness and toughness. The ideal PcBN is that there is no binder or the hardness of the binder is as close to cBN as possible, and it has suitable...

AI Technical Summary

Problems solved by technology

[0005] In summary, traditional PcBN binders include metal binders, ceramic binders and metal-ceramic composite binders, wherein metal binders are easily oxidized, soft, and have poor heat resistance (such as CN101627139A); ceramic binders have a high sintering temperature , low toughness (such as CN103030397A); and the metal-ceramic composite binder single element metal or alloy substance residue will reduce the high strength, hardness and heat resistance of PcBN, and the residue is unavoidable (such as CN102557647A)