Determination of microstructure and mechanical properties of functionally graded WC-TiC-Al2O3-GNPS micro-nano composite tool materials via two-step sintering

The effect of Al2O3-TiC additions on graded WC-Al2O3-TiC-GNPs composite synthesized employing two-step sintering was investigated. Al2O3-TiC additions with a proper weight ratio can not only facilitate the sintering but also make AAl(2)O(3) grains homogeneously distributed in the matrix and prompted the WC (0001) plane preferred orientation. Nano-grained TiC entered into the WC matrix and formed (Ti-0.8, W-0.2) C solid solution phase intragranular structure, which contributed to the formation of WC grains with irregular shape. High surface compressive stress, strong interface bonding, crack bridging, crack deflection and Al2O3 pullout are the major mechanisms contributing to the enhanced flexural strength and fracture toughness.