Mechanical property and cutting performance of (W, Ti)C based ceramic composites with the addition of nano-sized CaF2. (September 2021)

• Record Type: Journal Article
• Authors: Wang, Jianping; Yi, Mingdong; Xu, Chonghai; Xiao, Guangchun; Chen, Zhaoqiang; Zhang, Jingjie; Wang, Li
• Is Part Of: International journal of refractory metals & hard materials. Volume 99(2021)
• Publication Date: 2021-09
• Subjects: Ceramic cutting tool -- Nano-sized CaF2 -- Mechanical property -- Cutting performance; Heat resistant alloys -- Periodicals; Refractory materials -- Periodicals; Metallography -- Periodicals; Alliages réfractaires -- Périodiques; Matériaux réfractaires -- Périodiques; Métallographie -- Périodiques; Heat resistant alloys; Metallography; Refractory materials; Periodicals; Electronic journals; 669.73
• DOI: 10.1016/j.ijrmhm.2021.105607
• Languages: English
• ISSNs: 0263-4368

Abstract

Abstract: In order to improve the mechanical property of self-lubricating ceramic cutting tool, (W, Ti)C based ceramic composites with the additions of nano-sized CaF2 solid lubricants were produced by vacuum hot pressing. Results showed that nano-sized CaF2 was mainly located in matrix grains and formed the intragranular self-lubricating nanostructure. The optimal mechanical properties were achieved at 1650 °C and 15 min. The flexural strength, hardness and fracture toughness reaches the maximum of 497 MPa, 16.3GPa and 6.48 MPa·m 1/2, respectively. Compared with the ceramic composite without CaF2, the fracture toughness was increased by 13.0%. Dry machining tests of hardened 40Cr steel were performed with these ceramic cutting tools. It indicated that with the additions of nano-sized CaF2 as solid lubricant, the main cutting force and cutting temperature were reduced by 13.2% and 26.9%, the average friction coefficient of rake face was reduced from 0.59 to 0.32. SEM micrograph showed that a self-tribofilm was consistently formed on the rake wear area which has a good self-lubricating effect. Highlights: Nano-sized CaF2 solid lubricant is introduced into ceramic cutting tools. (W, Ti)C-based ceramic composites with nano-sized CaF2 solid lubricants were prepared by vacuum hot pressing method. The flexural strength, hardness and fracture toughness reaches the maximum of 497 MPa, 16.3GPa and 6.48 MPa·m 1/2 . CaF2 effectively reduces the coefficient of friction on the front face of the tool.