Phase Transformation during the Hot Pressing of WC-40vol.% Al₂O₃ Composites

Abstract:

WC matrix composites toughened by commercial Al₂O₃composed of AlOOH, χ-Al₂O₃and amorphous Al₂O₃ were prepared by high energy ball milling and then hot pressed at 769°C, 984°C, 1100°C, 1540°C for 90min, respectively, to investigate the phase transformation process. Microstructure and mechanical properties of WC-40vol.%Al₂O₃ composites were studied as well. The results showed that, with the increasing hot pressing temperature, the commercial Al2O3 transformed to α-Al₂O₃ completely through γ-Al₂O₃. WC could be oxidized and decarburized to W, C and W₂C at low temperature when the vacuum degree was very low. The existence of W in the composites sintered at 1540°C for 90min could contribute to a metal particle toughening effect to the composites, resulting in the achievement of an excellent fracture toughness of 10.43MPa•m^1/2, combining a Vickers hardness of 18.65GPa with a relative density of 97.98% for WC-40vol.%Al₂O₃ composites.

• Periodical: Applied Mechanics and Materials (Volumes 152-154)
• Pages: 260-265
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.152-154.260
• Online since: January 2012
• Authors: Hai Xia Qu, Shi Gen Zhu
• Keywords: Hot-Pressing, Mechanical Property, Microstructure, Phase Transformation, WC-Al₂O₃

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