Fabrication and evaluation of mechanical properties of polycrystalline diamond reinforced with carbon-nanotubes by HPHT sintering. Issue 13 (September 2020)

• Record Type: Journal Article
• Authors: Jian, Qi; Jiang, Ziling; Han, Yang; Zhu, Yumei; Li, Zhihong
• Is Part Of: Ceramics international. Volume 46:Issue 13(2020)
• Page Start: 21527
• Page End: 21532
• Publication Date: 2020-09
• Subjects: HPHT -- Carbon nanotubes -- PCD -- Mechanical properties -- Toughness; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2020.05.254
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: In this study, carbon nanotubes (CNTs) have been employed as reinforcements for polycrystalline diamond (PCD) to fabricate CNTs/PCD composites at high-pressure and high-temperature (HPHT, 5.5 GPa and 1550 °C) conditions. The microstructure, phase composition, elemental distribution, and the effect of CNTs on mechanical properties of CNTs/PCD composites were systematically investigated. Vickers hardness of the sample with 1.5 wt% CNTs reached to 58.3 GPa, while flexural strength was improved to 650.8 MPa. Fracture toughness was enhanced from 5.4 MPa m 1/2 to 9.1 MPa m 1/2, which was 68.5% higher compared with that of the monolithic PCD composites. Furthermore, the toughening mechanism was explored, the increase of fracture toughness is attributed to the pull-out and bridging of CNTs during crack deflection. Additionally, it was concluded that sintering time for 90 s in HPHT can effectively ensure the integrity of CNTs and guarantee their toughening effects. Highlights: CNTs/PCD composites with different contents of CNTs were fabricated by HPHT. Using multi-anvil apparatus to generate HPHT sintering conditions of 5.5 GPa, 1550 °C. A significant improvement of fracture toughness achieved 9.1 MPa m 1/2, which was 68.5% higher than that of the monolithic PCD composites. Rapid HPHT sintering can effectively ensure the integrity of CNTs to guarantee its toughening effects.