Abstract Full dense B4C–30 vol% TiB2 composites were prepared by hot pressing at 2000 °C under 35 MPa from four different starting B4C powders with their medium particle sizes ranging from 0.5 to 35.8 µm. The effects of B4C particle size on the microstructures and mechanical properties of composites were investigated. The results indicated that both B4C and TiB2 grains grew during sintering process, and each kind of grains had a pinning effect on the grain growth of the other. With coarse B4C powders as raw materials, TiB2 grains in obtained B4C–TiB2 composites tended to grow with the [001] zone axis parallel to the applied pressure direction, which possibly reinforced the composites. When the particle size of the starting B4C powder was 7.09 µm, the obtained B4C–TiB2 composite exhibited the optimized mechanical properties including a flexural strength of 754 MPa, a Vicker hardness of 30.01 GPa and a fracture toughness of 5.23 MPa m1/2, respectively, due to the most homogenous and finest microstructures.

中文翻译：

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B4C粒径对热压B4C-TiB2复合材料微观结构和力学性能的影响

摘要 用四种不同的起始 B4C 粉末在 2000 °C 和 35 MPa 下热压制备了全致密 B4C–30 vol% TiB2 复合材料，它们的中等粒径范围为 0.5 到 35.8 µm。研究了B4C粒径对复合材料微观结构和力学性能的影响。结果表明，B4C和TiB2晶粒在烧结过程中均生长，每种晶粒对另一种晶粒的生长有钉扎作用。以粗 B4C 粉末为原料，获得的 B4C-TiB2 复合材料中的 TiB2 晶粒倾向于以 [001] 区轴平行于施加压力方向的方式生长，这可能增强了复合材料。当起始 B4C 粉末的粒径为 7.09 µm 时，