【摘要】 采用渗硅反应烧结工艺制备了SiC/B4C复合材料,并研究了碳含量对复合材料的力学性能及微观结构的影响。结果表明,SiC/B4C复合材料的力学性能(硬度、抗弯强度、韧性)随着碳含量的增加呈先增强后减弱的趋势。在碳含量为10vol%的条件下,复合材料的综合性能最佳,其硬度、抗弯强度和韧性分别为19.63 Gpa、358 MPa和3.96 MPa?m1/2。此外,当碳含量不足10vol%,复合材料的组织随碳含量增加均匀性提高;当碳含量超过10vol%,显微组织均匀性变差,并且添加碳粉后,复合材料由沿晶、穿晶混合断裂向穿晶断裂转变,最终导致SiC/B4C复合材料力学性能的改变。更多还原

【Abstract】 SiC/B4 C composite was obtained by reaction sintering with Si infiltration, and the effects of carbon content on mechanical properties and the microstructure were investigated. The results showed that the mechanical properties of the SiC/B4 C composite improved firstly and then worsened with increasing carbon content. The optimum comprehensive properties of the composite were obtained by addition of 10vol% carbon. The hardness, bending strength, and fracture toughness of the composite were 19.63 GPa, 358 MPa and 3.96 MPa·m1/2, respectively. In addition, at carbon levels below 10vol%, the microstructure became more uniform as the carbon content increased. However, at carbon levels above 10vol%, the addition of carbon led to a fracture mode transformation, from combination of intergranular and transgranular to transgranular, which contributed to a change in the mechanical properties of the SiC/B4 C composite.更多还原