Polycrystalline cubic boron nitride was sintered under high temperature (1400 °C) and high pressure (5.5 GPa) using an in situ synthesis method. The composition, microstructure, relative density and mechanical properties of the polycrystalline cubic boron nitride (PcBN) with different contents of Gd2O3 were studied by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The results show that the phases of TiB2, TiN, AlN, AlTi2N and GdB6 are formed through in situ synthesis of cBN–Al–Ti–Gd2O3 system. With the Gd2O3 content increasing, the relative density increases and mechanical properties of PcBN begin to increase and then decrease. Proper amount of Gd2O3 can advance the formation of TiB2 and improve the aspect ratio of TiB2. When Gd2O3 content is 1.0 wt%, the PcBN exhibits optimal comprehensive mechanical properties, with a microhardness of 33.35 GPa and a flexural strength of 972.37 MPa.

中文翻译：

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不同Gd2O3添加量的cBN-Al-Ti体系中多晶立方氮化硼的原位合成

使用原位合成方法在高温 (1400 °C) 和高压 (5.5 GPa) 下烧结多晶立方氮化硼。采用X射线衍射(XRD)、扫描电子显微镜(SEM)和能量色散谱(EDS)等手段研究了不同Gd2O3含量的多晶立方氮化硼(PcBN)的组成、微观结构、相对密度和力学性能。 ）。结果表明，通过原位合成 cBN-Al-Ti-Gd2O3 体系，形成了 TiB2、TiN、AlN、AlTi2N 和 GdB6 相。随着Gd2O3含量的增加，PcBN的相对密度增加，力学性能先升高后降低。适量的Gd2O3可以促进TiB2的形成，提高TiB2的纵横比。当 Gd2O3 含量为 1.0 wt% 时，