Ternary boride reinforced Ti-based (C,N) metal ceramic material and preparation method thereof

Abstract

The invention discloses a ternary boride reinforced Ti-based (C,N) metal ceramic material and a preparation method thereof. The main preparation process comprises the following steps that Ti (C,N) metal ceramic raw material powder, carbide and nitride boride powder, binding phase raw material powder and binary boride powder are taken as raw materials, Ti-based (C,N) metal ceramic is prepared through the steps of ball milling mixing, drying, forming and sintering, wherein second phase ceramic particles generated by primary reaction are distributed in a binding phase of the metal ceramic material in a fine dispersion mode, the hardness and toughness of the metal ceramic material can be effectively improved through the phase. Compared with an existing technology for enhancing wear resistance,such as coating and surface treatment, the Ti-based (C,N) metal ceramic material prepared through the method has the advantages that the rockwell hardness reaches 91.5-94 HRA, the bending strength can reach 1800-2800 MPa, and the fracture toughness can reach 12-15 MPa.<-1 / 2>; and in addition, the depth of the grinding crack measured is reduced by about 70% compared with that of metal ceramic withthe same binding phase, and the friction coefficient is reduced by about 0.1.

Description

technical field [0001] The invention specifically relates to an in-situ generated ternary boride reinforced Ti(C,N)-based cermet material and a preparation method thereof, belonging to the field of metal matrix composite materials. Background technique [0002] Since Ti(C,N)-based cermet materials were first discovered in the 1970s, they have attracted widespread attention due to their high hardness, excellent wear resistance and red hardness. Ti(C,N)-based cermet material is a dense composite material prepared by liquid phase sintering technology with TiC, TiN or Ti(C,N) as the ceramic phase, metal Co and Ni as the binder phase. At present, the development of Ti(C,N)-based cermet materials is changing with each passing day, which is mainly reflected in the application of high-speed finishing and semi-finishing tools. Compared with WC-Co cemented carbide tool materials, Ti(C,N)-based The optimal cutting speed of cermets can usually be increased by 3 to 10 times, and can mai...

AI Technical Summary

Problems solved by technology

So far, the most commonly used toughening methods for cermets include increasing the content of binder phase and adding nanophases. Although increasing the content of binder phase can have a significant toughening effect, the high metal phase also greatly damages the toughness of the material. In addition, the addition of nano-phases can toughen the metal matrix through dispersion strengthening, but the agglomeration of nano-phases and the reaction of nano-phases during liquid phase sintering make the selection of nano-added phases more difficult

[0003] Ternary borides have excellent mechanical properties and wear and corrosion resistance, but few reports have been used as the strengthening and toughening phase of Ti(C,N)-based cermets, because B is easy to dissolve in the liquid phase during sintering. Segregation at the interface between the hard phase and the binder phase, or the formation of a brittle third phase, or solid solution in the metal binder phase, resulting in deterioration of the performance of the material

However, this preferentially grown strip-shaped ternary boride will cause stress concentration, and it is very easy to break due to the yield limit in the application process, resulting in component failure. Large, it is easy to fall off and become a hard point during the friction process, thereby increasing wear

In addition, during the high-temperature sintering process, due to the violent reaction to form ternary borides and the reaction temperature is lower than the liquidus temperature point, a large amount of surrounding Mo and Ni will be consumed during the growth of strip-shaped ternary borides. element, however, the Mo element is Mo 2 The main forming element of C and Mo 2 C can form a transition phase between the hard phase and the binder phase through a solid solution precipitation mechanism to improve the wettability of the two phases. Ni is one of the main elements of the binder phase and provides a certain toughness for the material; in boron After the compound was added, due to the preferential and rapid growth of the ternary boride produced by the reaction, the concentration of Mo and Ni elements around the ternary boride phase decreased sharply, which led to poor shell phase formation of the hard phase particles around the ternary boride. Sufficient, the liquid phase filling is not sufficient; it also leads to uneven distribution of the overall binder phase of the material

Images