Preparation method of strengthened polycrystalline cubic boron nitride composite super-hard material

The invention discloses a method for preparing a strengthened polycrystalline cubic boron nitride (PCBN) composite super-hard material by adding strengthened phases of super-hard materials such as cubic boron nitride c-BC2N, boron nitride (B4C) and nanometer twin crystal cubic boron nitride (nt-CBN) into a PCBN material, relating to a novel method for synthesizing a super-hard composite material by means of high-temperature and high-pressure sintering, and belongs to the field of super-hard materials. The method comprises the following steps: cutting a super-high-hardness material into a strengthened stem body; burying the strengthened stem body into powder, placing a pyrophyllite block and synthesizing under a high-temperature and high-pressure condition to obtain the PCBN material with a strengthened core. The strengthened PCBN composite super-hard material prepared by using the method has the toughness of PCBN as well as super high hardness which is comparable to that of a natural diamond material. The problems of higher and higher requirements on tools in the modern machining industry and the awkward situation of the application of certain super-high-hardness materials are solved, and the application field of the super-hard material is expanded.