烧结温度对原位反应TiB_2/B_4C复合材料的组织与力学性能的影响

Effects of Sintering Temperature on Microstructure and Mechanical Properties of TiB_2/B_4C Composites Fabricated by In-situ Reaction

为了降低B_4C的烧结温度,提高B_4C断裂韧性,本文以B_4C、TiO_2、活性炭为原料,采用原位反应法热压烧结制备了TiB_2体积分数为10％的TiB_2/B_4C复合材料。探索了烧结温度对复合材料组织和力学性能的影响规律。结果表明,随烧结温度的提高,复合材料的抗弯强度和断裂韧性先增大后减小,在2050℃时有最大值,分别为544MPa和6.3MPa·m^(1/2),弹性模量和断裂韧性变化不大。随烧结温度的升高,基体和第二相晶粒逐渐长大。采用2050℃/1h/35MPa为最佳烧结工艺。

In order to reduce the sintering temperature and increase the fracture toughness of the boron carbide, the in situ 10vol. %TiB_2/B_4C composite was produced by hot-pressing of B_4C with TiO_2 and C. It is shown that the flexural strength and fracture toughness of the TiB_2/B_4C composites increases firstly, and then decreases with increasing sintering temperature, reaching the maximum value at 2050 ℃. The fiexural strength and the fracture toughness of TiB_2/B_4C composite fabricated at 2050℃ are 544MPa and 6.3MPa. m^(1/2), respectively. The elastic modulus and Vickers hardness vary only slightly, and the grain diameter of matrix and reinforcement increases with increasing sintering temperature. The optimal sintering process is 2050℃/1h/35MPa.