热等静压原位合成SiC–TiC复相陶瓷的微观组织与性能研究

采用纳米级β-SiC粉末、Si粉末、C粉末以及微米级TiH_2粉末为原料,利用热等静压原位合成工艺制备了SiC–TiC复相陶瓷,研究了不同原位合成反应和烧结工艺对复相陶瓷微观组织及力学性能的影响。结果表明:以SiC、TiH_2、C粉末为原料的原位合成反应,无明显副反应发生,更有益于制备成分符合预期、致密度良好且性能优秀的SiC–TiC复相陶瓷。在1600℃,120 MPa,4 h等静压烧结工艺下原位合成得到的体积分数为SiC–32%TiC复相陶瓷具有最好的致密度、硬度、三点弯曲强度以及良好的断裂韧性,分别达到98.7%、21.2 GPa、428 MPa和5.5 MPa·m1/2。提高热等静压压力有助于提高材料的烧结扩散活性,从而提高材料的致密度,有益于力学性能的提升。

Microstructures and mechanical properties of SiC-TiC composites fabricated by hot isostatic pressing

SiC-TiC composites were successfully fabricated by hot isostatic pressing (HIP) usingβ-SiC, Si, C, and TiH2 powders as initial materials. Effects of sintering parameters on microstructures and mechanical properties were systematically investigated. In the results, the SiC-TiC composites are pure and full dense using SiC, TiH2, and C powders as the initial materials. The SiC-32vol% TiC composites sintered for 4 h at 1600℃ under 120 Mpa exhibit the highest relative density of 98.7%, highest Vickers hardness of 21.2 Gpa, highest flexural strength of 428 Mpa, and high fracture toughness of 5.5 Mpa·m1/2. Higher pressure contributes to enhancing the sintering activity of composites so as to improve the relative density and mechanical properties.