Interface Characteristics and High Temperature Wear Properties of Refractory Steel Matrix Composite Reinforced by Zoning CTCP/NiCrBSi

Abstract:

Using surface-modified cast tungsten carbide particles (CTC_P) as reinforcement, NiCrBSi alloy as binder phase and refractory steel as substrate, refractory steel matrix composite reinforced by zoning CTC_P/NiCrBSi was prepared by vacuum fusion sintering. Composite interface was observed and formation mechanism of composite interface was analyzed. Wear behaviors of the composite in the range of 25~800℃ were studied. Wear mechanisms of the composite were also discussed. The results showed that, theSstructure is compact and the CTC_P are evenly distributed in CTC_P/NiCrBSi area of composite; the interface between CTC_P/NiCrBSi area and refractory steel substrate is composed of three parts: CTC_P dissolution zone, γ-Ni isothermal-solidification zone and element spread influence zone rich in (Fe,Cr)-B; within the test temperature range, the wear rate of composite is less than that of refractory steel and both the wear rate and the relative wear resistance of the composite show the trend of decreasing and then increasing with the increase of the test temperature; the relative wear resistance of composite at 800℃ is the highest, reaching 1.8 times that of refractory steel; in the range of 25~600℃, the wear mechanisms of the composite are mainly micro-plowing, fatigue fracture induced by undergoing plastic deformation, CTC_P surface fatigue fracture caused by abrasive rolling and scratching, CTC_P broken or shedding due to insufficient NiCrBSi support; in the range of 600~800℃, the wear mechanism of composite are mainly micro-plowing and mutual promotion of oxidation and wear.