Al₂O₃/Ti composites containing 0‐30 vol% dispersed fine Ti particles were fabricated using a hot‐press sintering method at 1500°C from mixtures of Al₂O₃ and TiH₂ powders. During sintering, TiH₂ decomposed to form metallic Ti. The effects of the Ti content on the mechanical and electrical properties of the composites were then investigated. No Ti‐Al intermetallic compounds were detected by X‐ray diffraction, and energy‐dispersive X‐ray spectroscopy indicated the presence of Al‐Ti‐O solid solution and Ti‐O phases. The composites showed enhanced densification; the measured densities were higher than the calculated theoretical values. Microstructural observation revealed homogeneously distributed fine Ti particles dispersed in the Al₂O₃ matrix. The Ti particle size ranged from submicrometer to a few micrometers depending on the Ti content. The fracture mode of the composites was primarily transgranular, in contrast to the intergranular fracture mode of monolithic Al₂O₃. Although the flexural strength was decreased with increase in Ti content, the composite containing 20 vol% Ti displayed the maximum fracture toughness of 4.3 MPa·cm^1/2, which was 37% greater than that of monolithic Al₂O₃. The composites containing more than 15 vol% Ti exhibited drastic decreases in resistivity (~10⁻¹ Ωcm), which were attributed to the formation of interconnected Ti networks at these Ti contents. The percolation threshold volume for electrical conduction in the present system was calculated to be 13.8 vol%. The results indicate that dispersing fine Ti particles into Al₂O₃ increased the fracture toughness and improved the conductivity of Al₂O₃.

中文翻译：

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钛分散的精细Al2O3复合材料及其机械和电气性能

使用热压烧结法在1500°C下由Al ₂ O ₃和TiH ₂粉末的混合物制备了包含0-30％（体积）分散的Ti颗粒的Al ₂ O ₃ / Ti复合材料。烧结过程中，TiH ₂分解形成金属钛。然后研究了Ti含量对复合材料的机械和电气性能的影响。X射线衍射未检测到Ti-Al金属间化合物，能量色散X射线光谱表明存在Al-Ti-O固溶体和Ti-O相。复合材料显示出更高的致密性；测量的密度高于计算的理论值。显微组织观察表明，均匀分布的Ti细颗粒分散在Al ₂ O ₃基体中。Ti的粒径根据Ti的含量在亚微米至几微米的范围内。复合材料的断裂模式主要是跨晶的，与整体式Al的晶间断裂模式相反₂ O ₃。尽管随着Ti含量的增加，抗弯强度降低，但含20％（体积）Ti的复合材料的最大断裂韧性为4.3 MPa·cm ^1/2，比整体式Al ₂ O _3高37％。含有复合材料的超过15体积％的Ti展出急剧降低电阻率（〜10 ^-1 Ωcm以下），其归因于在这些钛含量的形成相互连接的Ti网络。在本系统中，导电的渗透阈值体积经计算为13.8vol％。结果表明，将Ti细颗粒分散到Al ₂ O _3中增加了断裂韧性并提高了Al ₂ O ₃的电导率。