High hardness and high fracture toughness B4C-diamond ceramics obtained by high-pressure sintering. Issue 8 (July 2023)

• Record Type: Journal Article
• Authors: Lai, Shoulong; Zang, Jinhao; Shen, Weixia; Huang, Guofeng; Fang, Chao; Zhang, Yuewen; Chen, Liangchao; Wang, Qianqian; Wan, Biao; Jia, Xiaopeng; Zhang, Zhuangfei
• Is Part Of: Journal of the European Ceramic Society. Volume 43:Issue 8(2023)
• Page Start: 3090
• Page End: 3095
• Publication Date: 2023-07
• Subjects: Ceramic-matrix composites -- Fracture toughness -- Hardness -- Mechanical properties -- Microstructures; Ceramic materials -- Periodicals; Composite materials -- Periodicals; Matériaux céramiques -- Périodiques; Composites -- Périodiques; Ceramic materials; Composite materials; Periodicals; Electronic journals; 666.05
• DOI: 10.1016/j.jeurceramsoc.2023.01.044
• Languages: English
• ISSNs: 0955-2219

Abstract

Abstract: The B4 C-diamond composite with high hardness and toughness was first prepared by high-pressure sintering of B4 C and diamond powders at 5 GPa and 1600 °C. The effect of the diamond fraction on the densification, microstructure and mechanical properties of B4 C-diamond composite were investigated. The results indicated that the hardness of the as-prepared composite ceramics increased gradually with the increase in diamond content. The composite having 40 vol% diamond exhibited excellent comprehensive mechanical properties with a relative density of 98.3%, a density of 2.86 g/cm 3, Vickers hardness of 39.8 GPa and fracture toughness of 8.1 MPa·m 1/2 . The use of superhard diamond enhanced the fracture toughness of the B4 C while maintaining its lightweight and high hardness. The main toughening mechanisms were crack bridging, crack deflection and pull-out of homogeneously dispersed diamond grains. Superhard second phase dispersion high-pressure sintering provides a new technical route to improve the properties of advanced composites. Highlights: B4 C-diamond ceramics were firstly fabricated by high pressure sintering. The phase change from diamond to graphite is avoided during the sintering process. The Vickers hardness of B4 C-50 vol% cBN composite reached up to 41 GPa. The fracture toughness of the B4 C-40 vol% diamond composite was 8.1 MPa·m 1/2 .