Investigation of Microstructure and Machinable Mechanism of the B₄C/BN Composites Fabricated by Hot-Pressing Process

Abstract:

The B₄C/BN composites were fabricated by hot-pressing process. The B₄C/BN composites included the B₄C/BN microcomposites and the B₄C/BN nanocomposites. The B₄C/BN microcomposites were fabricated by hot-pressing process, and the B₄C/BN nanocomposites were fabricated by chemical reaction and hot-pressing process. In this research, the phase composition, microstructure, machinability and machinable mechanism of the B₄C/BN microcomposites and the B₄C/BN nanocomposites were investigated. The microstructure of the B₄C/BN composites was investigated by SEM and TEM. The SEM micrographs showed that the B₄C/BN microcomposites and the B₄C/BN nanocomposites exhibited the homogenous and compact microstructure, and the h-BN particles were homogenously distributed in the B₄C matrix. The TEM micrographs of the B₄C/BN composites showed that there existed the weak interface between B₄C matrix grains and h-BN particles as well as the microcracks within the laminate structured h-BN particles. The machinability of the B₄C/BN microcomposites and the B₄C/BN nanocomposites increased gradually with the increase of h-BN content. The drilling rates and materials removal rates of the B₄C/BN composites increased gradually with the increase of h-BN content. The surface roughness of drilled specimens of the B₄C/BN composites decreased gradually with the increase of h-BN content. The relationship between the microstructure and machinable mechanism of the B₄C/BN composites was analyzed and discussed. The phase composition and microstructure of drilled debris of drilled specimens of the B₄C/BN composites were investigated by XRD and TEM. The microstructure of drilled surface of drilled specimens of the B₄C/BN composites was observed and analyzed by SEM.

• Periodical: Advanced Materials Research (Volume 413)
• Pages: 420-425
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.413.420
• Online since: December 2011
• Authors: Tao Jiang
• Keywords: B₄C/BN Composites, Hot-Pressing Process, Machinability, Mechanism, Microstructure

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