Abstract
The microstructure and micro-hardness of tungsten carbide/high strength steel (WC/HSS) composites with different particle sizes were analyzed by optical microscopy (OM), scanning electron microscopy (SEM), ultra-high temperature laser confocal microscopy (UTLCM) and micro-hardness testing. The composites were prepared by cold pressing and vacuum sintering. The results show that WC density tends to increase as the average grain size of WC decreases and the micro-hardness of WC increases with the decrease of WC particle size. The micro-hardness of WC near the bonding interface is higher than that in other regions. When the particle size of WC powder particles is 200 nm, a transition layer with a certain width is formed at the interface between WC and HSS, and the combination between the two materials is metallurgical. The iron element in the HSS matrix diffuses into the WC structure in contact with it, resulting in a fusion layer of a certain width, and the composite interface is relatively well bonded. When the average particle size of WC powder is 200 nm, W, Fe and Co elements significantly diffuse in the transition zone at the interface. With the increase of WC particle size, the trend of element diffusion decreases.
Highlights
Tungsten carbide (WC) materials are widely used in micro-drills, nuclear refractory parts, medical equipment, cutting tools and wear-resistant parts due to their attractive properties such as high hardness, high melting point, high density, high wear resistance and corrosion resistance [1,2,3,4]
In order to study the effect of particle size of tungsten carbide on the microstructures of tungsten
In order to study the effect of particle size of tungsten carbide on the microstructures of carbide/high strength steel composites, ultrafine tungsten carbide powders with average particle sizes tungsten carbide/high strength steel composites, ultrafine tungsten carbide powders with average of 100, 200, 300 and 500 nm were selected
Summary
Tungsten carbide (WC) materials are widely used in micro-drills, nuclear refractory parts, medical equipment, cutting tools and wear-resistant parts due to their attractive properties such as high hardness, high melting point, high density, high wear resistance and corrosion resistance [1,2,3,4]. Research on WC particle reinforced steel matrix composites mainly focused on the influence of sintering temperature, holding time, preformed pressure and other process parameters, on the microstructure, properties and interface of the composite. These studies were carried out under conditions in which the particle size of the tungsten carbide particles was kept constant, and the influence of the particle size of the tungsten carbide particles on the microstructure, properties and interface of the composite material was not considered. Most of the existing research has focused on the manufacture of macro-scale parts [15], while tungsten carbide/steel composites for small parts have rarely been reported
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