C/C-ZrC复合材料的微观结构和力学性能研究

Microstructure and Mechanical Properties of C/C-ZrC Composites

采用ZrOCl2溶液浸渍法把锆化合物引入碳纤维预制体,经热处理、热梯度化学气相渗透致密化和高温石墨化工艺制备了C/C-ZrC复合材料。性能测试结果表明,C/C复合材料的弯曲强度和模量随ZrC含量的增加而增大,ZrC含量为12.08wt%时,其强度和模量分别为42.5 MPa和9.6 GPa,比未改性试样分别提高了70.0%和43.3%。基体中结合较弱的微米级ZrC颗粒的存在不利于碳基体强度的提高,但其对材料最终性能的影响是次要的,碳基体中亚微米/纳米级ZrC颗粒的存在和良好的ZrC-C界面结合,提高了碳基体的强度和模量,进而提高了复合材料的最终性能。

C/C-ZrC composites were obtained by subsequent steps： immersing carbon felts into Zr OCl2 aqueous solution, heat treatment, densification by thermal gradient chemical vapor infiltration with methane gas and graphitization. Three-point bending tests were performed to evaluate the mechanical properties of the composites. The results show that the flexural strength and elastic modulus increase with increasing ZrC contents. Carbon/carbon（C/C） composites containing 12.08wt% ZrC achieve a flexural strength of 42.5 MPa and a modulus of 9.6 GPa, increasing by 70.0% and 43.3%, respectively, as comparison with the flexural strength and modulus of C/C composites. Micro-size ZrC particles with weak anchoring strength between them are unfavorable to the strength of carbon matrices, but they are not the main determinant of the strength of the composites. Submicro-and nano-size ZrC particles in carbon matrices owning good interface anchoring strength with carbon matrices can enhance the strength and elastic modulus of carbon matrices, improving the final mechanical properties of the composites.