Phase Composition and Microstructure of Binderless WC-ZrC Cemented Carbides Fabricated by Spark Plasma Sintering

Abstract:

Binderless WC-based cemented carbides with different fractions (0-9 wt.%) of ZrC nanopowder were fabricated through spark plasma sintering at 1600 °C under a uniaxial pressure of 50 MPa. The addition effect of ZrC nanopowder on the phase composition and microstructure of the fabricated materials were explored with the help of X-ray diffraction and scanning electron microscope. The results indicated that W₂C phase was detected in the samples with 0-3 wt.% ZrC nanopowder, but with further increase in ZrC added fraction, ZrO₂ phase instead of W₂C phase was detected. The apparent density decreased gradually with the increase in added fraction of ZrC nanopowder, while the relative density increased initially and then decreased, reaching its maximum of about 98.2% when the added fraction of ZrC nanopowder was about 3 wt.%, indicating that appropriate added fraction of ZrC nanopowder can improve the densification of binderless WC cemented carbides. Without ZrC nanopowder, the coarsening and abnormal growth of WC grains were serious, resulting in many large prismatic WC grains in the samples. However, Such phenomena could be suppressed by adding ZrC nanopowder, resulting in much finer and more homogenous microstructure after 1-3 wt.% ZrC nanopowder was added. When the added fraction of ZrC nanopowder was higher than 3 wt.%, the agglomeration of ZrC nanopowder became more and more serious.

• Periodical: Key Engineering Materials (Volumes 602-603)
• Pages: 556-560
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.602-603.556
• Online since: March 2014
• Authors: Xiao Yong Ren, Zhi Jian Peng, Hui Yong Rong, Ying Peng, Cheng Biao Wang, Zhi Qiang Fu, Long Hao Qi, He Zhuo Miao
• Keywords: Microstructure, Spark Plasma Sintering (SPS), WC-Based Materials, ZrC Nanopowder

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