Fibrous nano composite reinforced surface on WC-Co cemented carbide achieved by pulsed electron beam irradiation and subsequent tempering

Wenhai Peng,Limin Zhao,Shengzhi Hao,F Yan,Y Long,X Hou,M Li

doi:10.1051/e3sconf/202126801078

Abstract

Exotic microstructures can be tailored by extreme conditions with combined material processing techniques for desirable properties. In this work, an innovative 2-staged process was explored for WC-10Co cemented carbide surface modification. Firstly, rapid thermal cycles were induced by high current pulsed electron beam (HCPEB) irradiation at energy density of 6 J/cm2, during which the micro-WC/Co was melted and re-solidified into a nano-scaled equiaxed grain microstructure with metastable fcc-WC1-x as the majority phase in the surface layer (~2 μm). Thereafter, a subsequent tempering process was applied to the HCPEB-irradiated cemented carbide specimens and the nano equiaxed grains in the surface layer were gradually transferred into nano-scaled fibrous microstructure. Phase transformation was investigated using thermo-gravimetric analysis differential scanning calorimetry (TGA-DSC), confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM) and X-ray diffractometry (XRD). Analysis showed that the fibrous nano structure resulted from the decomposition of WC1-x at 600-700 ºC via fcc-WC1-x → hex-WC + hcp-W2C. After the 2-staged process, the surface microhardness was greatly improved.

Highlights

Cemented tungsten carbide holds excellent mechanical properties such as high hardness, fracture strength and wear resistance, has been widely used as drilling, cutting, machining tools[1,2]
Considering the metastability of the high current pulsed electron beam (HCPEB)-induced microstructure, it is possible that with proper post-HCPEB thermal treatment, this modified surface would undergo a series of solid state phase transformations, resulting in the formation of a surface layer at more stable state with further enhanced property
WC-10Co cemented carbide was subjected to a 2-stage process, i.e., HCPEB irradiation and the subsequent tempering treatment

Summary

Introduction

Cemented tungsten carbide holds excellent mechanical properties such as high hardness, fracture strength and wear resistance, has been widely used as drilling, cutting, machining tools[1,2]. Considering the metastability of the HCPEB-induced microstructure, it is possible that with proper post-HCPEB thermal treatment, this modified surface would undergo a series of solid state phase transformations, resulting in the formation of a surface layer at more stable state with further enhanced property. WC-10Co cemented carbide was subjected to a 2-stage process, i.e., HCPEB irradiation and the subsequent tempering treatment. A nano fibrous composite was formed on the surface of the cemented carbide after the 2-stage process. Microstructure evolution was analyzed to elucidate the mechanism of the solid-state phase transformation leading to the formation of the fibrous composite surface

Methods

Results

Conclusion