FLiNaK熔盐浸渗对2D C/C复合材料力学性能的影响

Influence of FLiNaK Salt Impregnation on Mechanical Properties of 2D Woven C/C Composite

在650℃不同压力下将熔融的LiF-NaF-KF盐(46.5%-11.5%-42.0%,摩尔分数,FLiNaK)浸渗入2D C/C复合材料中,测试2D C/C复合材料的增重率、密度和力学性能的变化并用X射线断层扫描(X-ray CT)和扫描电子显微镜(SEM)观察FLiNaK熔盐的分布,研究了FLiNaK熔盐浸渗对2D C/C复合材料力学性能的影响。结果表明,FLiNaK熔盐分布在2D C/C复合材料开放的孔隙中、纤维束中和相邻层的裂缝中;随着浸渗压力的提高2D C/C复合材料的增重率增大、压缩强度和弯曲强度提高。FLiNaK熔盐浸渗产生的"二次增密"作用和2D C/C复合材料中残余应力的耦合效应,使其力学性能提高。

Impregnating molten LiF-NaF-KF salt (46.5%-11.5%-42.0%,mole fraction,FLiNaK) into a2D woven C/C composite was performed at 650℃under different pressure.The mass gain,the change of density and mechanical properties of the 2D woven C/C composite after FLiNaK salt impregnation were measured.The FLiNaK salt distribution in the 2D woven C/C composite was observed by X-ray CT and SEM.The results show that the mass gain of the 2D woven C/C composite increased with the increasing impregnation pressure.FLiNaK salt distributed within open pores of the composite and fissures of fiber bundles and interlaminar fractures.The compressive strength and flexural strength of the 2D woven C/C composite increased with the increasing impregnation pressure.The coupling effect of densification induced by FLiNaK salt impregnation and residual stress formed in 2D woven C/C composite could be benefitial to the mechanical property of the C/C composite.