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基于熔融Si浸渗法制备出较致密的SiC/TiB_2复合材料,并研究了坯体成形压力对SiC/TiB_2复合材料致密度、相组成、显微组织和力学性能的影响。实验结果表明,复合材料由TiB_2、Si C和Si相组成。SiC/TiB_2复合材料的显微组织特征为:TiB_2相和SiC相均匀分布,游离Si填充在TiB_2相和SiC相的空隙处,且形成了连续相。随成形压力的增大,复合材料中游离Si含量降低,TiB_2颗粒尺寸减小,复合材料的力学性能先增加后降低。坯体最佳成形压力为200 MPa,对应SiC/TiB_2复合材料的体积密度、开口气孔率、抗弯强度、断裂韧性和维氏硬度分别为3.63 g/cm~3、0.90%、(354±16)MPa、(6.8±0.2)MPa·m~(1/2)和(21.0±1.1)GPa。
The more compact SiC / TiB 2 composites were prepared by melt infiltration method and the effect of forming pressure on the density, phase composition, microstructure and mechanical properties of SiC / TiB 2 composites was studied. The experimental results show that the composites consist of TiB 2, Si C and Si phases. The microstructure of SiC / TiB_2 composites is characterized by uniform distribution of TiB 2 phase and SiC phase, free Si filling in the space of TiB 2 phase and SiC phase, and the formation of continuous phase. With the increase of forming pressure, the content of free Si in the composites decreases and the size of TiB 2 particles decreases. The mechanical properties of the composites first increase and then decrease. The optimum forming pressure of the green body is 200 MPa, corresponding to bulk density, open porosity, flexural strength, fracture toughness and Vickers hardness of 3.63 g / cm ~ 3, 0.90% and 354 ± 16 ) MPa, (6.8 ± 0.2) MPa · m ~ (1/2) and (21.0 ± 1.1) GPa.