ZrC和ZrB_(2)对C_(sf)/SiC-BN-(ZrC,ZrB_(2))复合材料组织及力学性能的影响

Effects of ZrC and ZrB_(2)on Microstructure and Mechanical Properties of C_(sf)/SiC-BN-(ZrC,ZrB_(2))Composites

以微米级陶瓷粉体和短切碳纤维为原料,经1800℃热压烧结制备了C_(sf)/SiC-BN-(ZrC,ZrB_(2))陶瓷基复合材料。采用力学性能测试、XRD、SEM等方法研究了ZrC和ZrB_(2)对C_(sf)/SiC-BN-(ZrC,ZrB_(2))复合材料界面反应、显微组织和力学性能的影响规律。结果表明:C_(sf)/SiC-BN-ZrC复合材料的断裂韧度达到8.83 MPa·m^(1/2),纤维与基体的界面反应较弱。随着ZrB_(2)的加入,C_(sf)/SiC-BN-ZrC-ZrB_(2)和C_(sf)/SiC-BN-ZrB_(2)复合材料的弯曲强度得到提升,但界面反应也明显加剧,断裂韧度分别下降至5.92 MPa·m^(1/2)和5.59 MPa·m^(1/2)。添加ZrB_(2)会加剧界面反应,导致碳纤维退化和复合材料断裂韧度降低。

Using micro-sized ceramic powders and chopped carbon fibers as raw materials,C_(sf)/SiC-BN-(ZrC,ZrB_(2))ceramic matrix composites were prepared by using hot pressing technique at 1800℃.The effect of ZrC and ZrB_(2)on interfacial reaction,microstructure and properties of the composites were carefully studied by using XRD,SEM and mechanical property testing.The C_(sf)/SiC-BN-ZrC composite exhibited preferable fracture toughness(8.83 MPa·m^(1/2))and weak interfacial reaction between the carbon fibers and the ceramic matrix.With the addition of ZrB_(2),bending strength of the C_(sf)/SiC-BN-ZrC-ZrB_(2)and C_(sf)/SiC-BN-ZrB_(2)composites was increased,but the interfacial reaction became more serious and the fracture toughness decreased to 5.92 MPa·m^(1/2)and 5.59 MPa·m^(1/2),respectively.In conclusion,the addition of ZrB_(2)intensified the interfacial reaction,resulting in the degradation of carbon fibers and the reduction in toughness of the composites.