Dense and core-rim structured B4C-TiB2 ceramics with Mo-Co-WC additive |
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| Authors: | Da-Wang Tan Zhen-Yong Lao Zhan Zhang Wei-Ming Guo Shi-Kuan Sun Hua-Tay Lin |
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| Affiliation: | 1. School of Electromechanical Engineering, Guangdong University of Technology, Guangzhou, China;2. Department of Materials Science and Engineering, University of Sheffield, Sheffield, UK |
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| Abstract: | B4C-TiB2 ceramics (TiB2 ranging 5~70 vol%) with Mo-Co-WC as the sintering additive were prepared by spark plasma sintering. In comparison with B4C-TiB2 without additive, the enhanced densification was evident in the sintered specimen with Mo-Co-WC additive. Core-rim structured grain was observed around TiB2 grains. The interface of the rim between TiB2 and B4C phases demonstrated different feature: the inner borderline of the rim exhibited a smooth feature, whereas a sharp curved grain boundary was observed between the rim and the B4C grain. The formation mechanism is discussed: the epitaxial growth of (Ti,Mo,W)B2 rim around the TiB2 core may occur as a result of the solid solution and dissolution-precipitation between TiB2 phase and the sintering additive. It was revealed that the fracture toughness increased as the content of TiB2 content increased, alongside the decreased hardness. B4C-30 vol% TiB2 specimen demonstrated the optimal combination of mechanical properties, reaching Vickers hardness of 24.3 GPa and fracture toughness of 3.33 MPa·m1/2. |
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| Keywords: | B4C-TiB2 ceramic core-rim structure fracture toughness sintering additives Vickers hardness |
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