Preparation method of multifunctional gradient composite ceramic cutting tool material

Abstract

The invention belongs to the field of mechanical manufacturing, more particularly relates to a preparation method of a multifunctional gradient composite ceramic cutting tool material. The method takes hard alloy with high strength, high tenacity and high elastic modulus as reinforced materials, wherein an upper layer is WC-based nano composite powders including WC, ZrO2 and Al2O3 (WZA), and a bottom layer is hard alloy powders including WC and Mo(WM); or the upper layer and the lower layer are WC-based nano composite powders (WZA), and a middle layer is hard alloy powders(WM); and the reinforced materials are hot-pressed and sintered at the atmosphere of nitrogen. The flexural strength, the fracture toughness property, the wear-resisting property, and the like of the cutting tool material are improved by utilizing the high hardness, the high chemical stability and the high wearing-resisting property of the WC-based nano composite material and the high strength and the high fracture toughness of the hard alloy. Compared with the general hard alloy cutting tool, the hardness of the multifunctional gradient composite ceramic cutting tool material is improved by 15-20 percent; and compared with the ceramic cutting tool, the flexural strength and the fracture toughness of the multifunctional gradient composite ceramic cutting tool material are respectively improved by 30-40 percent and 25-40 percent.

Description

technical field [0001] The invention belongs to the field of mechanical manufacturing, in particular to a preparation method of a multifunctional gradient composite ceramic tool material. Background technique [0002] Among the current tool materials, new nanocomposite tool materials, especially ceramic-based nanocomposite tool materials, are widely used in high-speed cutting due to their unique properties such as high hardness, wear resistance, high temperature resistance and good chemical stability. fields are widely used. The Chinese patent No. 89108322.7 discloses a ZrO 2 Reinforced Al 2 o 3 The matrix composite ceramic material has good chemical stability. In addition, since Al 2 o 3 The solubility in iron is only 1 / 5 of that of WC in iron, and it is not easy to bond and diffuse with iron-based workpiece materials during processing. Therefore, it has a strong advantage in processing cast iron workpiece materials. However, Al 2 o 3 The disadvantages of low stren...

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Problems solved by technology

However, Al 2 o 3 The disadvantages of low strength, fracture toughness, thermal conductivity and thermal shock resistance of the base ceramic limit its application range, and it is prone to damage during cutting, resulting in a significant reduction in tool life

Such as Deng Jianxin (Deng Jianxin, Liu Lili, Liu Jianhua, et al. Failure mechanisms of TiB 2 particle and SiC whisker reinforced Al 2 o 3 TiB developed by ceramic cutting tools when machining nickel-based alloys. International Journal of Machine Tools and Manufacturing, 45(2005): 1393-1401) et al. 2 and SiC reinforced Al 2 o 3 Ceramic-based tool materials, when machining nickel-based alloys, have a shorter life due to lower strength and fracture toughness

In addition, the conductivity of ceramic-based tool materials is poor, and there are serious defects in the processing of welding tools, and its application range is limited

The Chinese patent No. 02139711.2 discloses a WC-based (WC-Co) cemented carbide, which is widely used for its good machinability, high strength and fracture toughness, and high thermal conductivity. However, due to the low softening point temperature of the binder metal Co, the tool material will soften prematurely in high-speed cutting

At the same time, the chemical activity of Co is high, and it is very easy to react with other elements at high temperature, resulting in serious diffusion of the tool.