The evolution of microstructure and mechanical properties of TiB–7.5 wt% WC-based cermets sintered at different temperatures were investigated. The results showed that eutectic liquid phase appeared at around 1335 °C, indicating that solid-phase sintering occurred below that temperature, while liquid-phase sintering occurred above that temperature. TiB, WCoB, WB and CoNi phases were detected in the XRD patterns of cermets sintered at different temperatures, and TEM analysis showed the presence of TiC phase. So the following chemical reaction should occur: TiB + WC + Co → WCoB + WB + TiC. The TiB core - (Ti, W, Co, Ni)(B, C) rim phase were observed in the cermet sintered at 1397 °C. As the increase of sintering temperature, the solubility of WC and TiB in CoNi binder phase, and the number of core-rim structure hard phase particles increased. The formation of core-rim structure enhanced the interfacial bonding strength between TiB phase and CoNi binder, which was beneficial for improving the strength and toughness of cermets. The cermets sintered at 1465 °C had good comprehensive mechanical properties, with a relative density of 99.62%, a hardness of 17.34 ± 0.43 GPa, a transversal rupture strength of 2038 ± 53 MPa, and an indentation fracture toughness of 12.15 ± 0.32 MPa·m.

中文翻译：

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不同温度烧结TiB2-7.5 wt.% WC基金属陶瓷的微观结构和力学性能的演变


研究了不同温度下烧结的 TiB-7.5 wt% WC 基金属陶瓷的微观结构和机械性能的演变。结果表明，共晶液相出现在1335 ℃左右，表明低于该温度发生固相烧结，而高于该温度则发生液相烧结。不同温度烧结的金属陶瓷的 XRD 图谱中检测到 TiB、WCoB、WB 和 CoNi 相，TEM 分析表明存在 TiC 相。因此应发生以下化学反应：TiB + WC + Co → WCoB + WB + TiC。在 1397 °C 烧结的金属陶瓷中观察到 TiB 核 - (Ti, W, Co, Ni)(B, C) 边缘相。随着烧结温度的升高，WC和TiB在CoNi粘结相中的溶解度以及核-边结构硬质相颗粒的数量增加。芯环结构的形成增强了TiB相与CoNi粘结剂之间的界面结合强度，有利于提高金属陶瓷的强度和韧性。 1465 ℃烧结的金属陶瓷具有良好的综合力学性能，相对密度为99.62%，硬度为17.34±0.43 GPa，横向断裂强度为2038±53 MPa，压痕断裂韧性为12.15±0.32 MPa·米。