Effect of VC addition on the microstructure and properties of TiC steel-bonded carbides fabricated by two-step sintering

• Published in: International journal of refractory metals & hard materials Vol. 108; p. 105948
• Main Authors: Chen, Meng, Zheng, Yong, Guo, Xiaoge, Liang, Haifeng, Xu, Xiangyu, Yang, Min, Jiang, Zhiyi, Zhu, Xinggen
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.11.2022
• Subjects: High-temperature oxidation behavior; Mechanical properties; Microstructure; TiC steel-bonded carbide; Mechanical properties; High-temperature oxidation behavior; Microstructure; TiC steel-bonded carbide; VC
• ISSN: 0263-4368; 2213-3917
• DOI: 10.1016/j.ijrmhm.2022.105948

The effect of VC addition on microstructure, mechanical properties and high-temperature oxidation behavior of the TiC steel-bonded carbides, fabricated by two-step sintering, were examined by SEM, EDS, and XRD. The results show that an appropriate amount of VC enables the TiC steel-bonded carbide to further refine the hard phase particles while maintaining high density. When the VC addition amount is not higher than 0.8 wt%, the hard phase particles are gradually refined with the increase of VC content. The added VC is mainly distributed in the rim phase around the hard phase particles, which inhibits the dissolution and precipitation of TiC and thus refines the grains. When the VC addition amount reaches 1.2 wt%, the excess VC raises the possibility of particle agglomeration or segregation, which will coarsen the rim phase and degrade the mechanical properties. Overall, TiC steel-bonded carbides with 0.8 wt% VC possesses superior comprehensive mechanical properties. Moreover, when TiC steel-bonded carbides are oxidized at a constant temperature of 750 °C, their high-temperature oxidation behavior follows a parabolic law. The oxidation rate is mainly controlled by the surface chemical reaction rate in the early stage and the oxygen ion diffusion rate in the later stage. •Series of TiC steel-bonded carbides with different VC content were firstly fabricated by two-step sintering technology.•Microstructures, mechanical properties and high-temperature oxidation behavior were firstly studied.•An appropriate amount of VC refines the hard phase particles while maintaining a high density of TiC steel-bonded carbides.•The as-prepared TiC steel-bonded carbides show excellent mechanical properties.