SiC_(f)/SiC复合材料致密化过程模拟  

Simulation of Densification Process of SiC_(f)/SiC Composites

作　　者：刘瑶瑶 海维斌 彭雨晴 李爱军[1] 张方舟 LIU Yaoyao;HAI Weibin;PENG Yuqing;LI Aijun;ZHANG Fangzhou(School of Materials Science and Engineering,Shanghai University,Shanghai 201800,China)

机构地区：[1]上海大学材料科学与工程学院,上海201800

出　　处：《陶瓷学报》2022年第4期674-683,共10页Journal of Ceramics

基　　金：上海市自然科学基金(20ZR1419600);上海市轻质结构复合材料重点实验室开放课题基金(2232019A4-05);先进功能复合材料技术重点实验室基金项目(6142906200110);国家自然科学基金(21676163)。

摘　　要：在等温化学气相渗透条件下对二维叠层SiC纤维预制体的致密化过程进行模拟,根据传质过程和反应动力学计算得到双活性位竞争模型和孔隙演变过程。结果显示,预制体束内10μm以下的小孔优先被填充,随后束间孔隙逐渐被填充变为小孔,当孔隙率降至20%时,预制体内部存在约为50μm的等效孔隙。预制体比表面积的变化存在两个阶段,孔隙率为40%以上时,比表面积减小的速度较快。特定工艺条件下模拟结果显示复合材料密度在2.48 g·cm^(−3)~2.38 g·cm^(−3)范围内,与实际样品最大误差0.73%;孔隙率在13.94%~17.75%范围内,与实际样品最大误差为4.21%。气相组分浓度变化表明此工艺条件下更易生成富硅的复合材料。The densification process of 2D laminated SiC fiber preform was simulated under the condition of isothermal chemical vapor infiltration.According to the mass transfer process and reaction kinetics calculations,the dual active site competition model and the pore evolution process are developed.It was found that the pores which are smaller than 10μm in the preform bundle are preferentially filled,so that the pores between the bundles are gradually filled into the small ones.When the porosity is reduced to 20%,there are equivalent pores of about 50μm inside the preform.There are two stages in the variation of specific surface area of the preform.When porosity is above 40%,the specific surface area decreases quickly.The simulation results under specific process conditions indicate that densities of the composite are in the range of 2.48–2.38 g·cm^(−3),while the maximum error is 0.73%.The porosity is in the range of 13.94%–17.75%,with maximum error to be 4.21%.Changes in gas-phase component concentrations indicate that silicon-rich composites are more likely to be formed under this process condition.

关 键 词：SiC_(f)/SiC复合材料 化学气相渗透 双活性位竞争模型 孔隙演变 

分 类 号：TQ174.75[化学工程—陶瓷工业]