Densification and characterization of hot-pressed ZrC-based composite doped with Nb and CNT. (15th August 2016)

• Record Type: Journal Article
• Authors: Li, Jian; Zhang, Zhaofu; Wang, Shouhao; Wang, Yongchang; Dai, Jixiang; Zu, Yufei; Sha, Jianjun
• Is Part Of: Materials & design. Volume 104(2016)
• Page Start: 43
• Page End: 50
• Publication Date: 2016-08-15
• Subjects: ZrC -- Nb -- CNT -- Microstructure -- Mechanical properties; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2016.05.003
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: ZrC-based composite doped with 20 vol.% niobium (Nb) and 3 vol.% carbon nanotubes (CNT) was prepared by hot pressing. Due to the addition of Nb and CNT, the sinterability of ZrC was significantly improved, resulting in highly dense matrix (99.28%) at reduced sintering temperature (1600 °C). The flexural strength was 590 MPa at room temperature and 563 MPa at 800 °C, respectively. The fracture toughness was 7.23 MPa·m 1/2, which increased by 80% compared with the monolithic ZrC (4 MPa·m 1/2 ). In addition, the work of fracture was calculated to be 267 J/m 2 . Based on the microstructure characterizations, the improved fracture properties could be attributed to crack deflection, crack bridging and crack branching, which consumed more fracture energy during the fracture process. Graphical abstract: Highlights: ZrC-based ultra-high temperature ceramic composite (ZNC) was prepared in this paper, which is composed of ZrC + 20Nb + 3CNTs (vol.%). Highly dense ZNC with a relative density of 99.28% was obtained at 1600 °C by hot pressing. The ZNC showed a fracture toughness of 7.23 MPa·m1/2, which increased by 80% compared with the monolithic ZrC ceramic.