摘要：
C/C-SiC composites were prepared by the combined process of chemical vapor infiltration (CVI) and gaseous silicon infiltration (GSI) using C/C green body with the density of 1 .0g/cm3 . Effect of CVI C/C-SiC intermediate composites' density on the phase composition ,microstructure and mechanical properties of CVI-GSI C/C-SiC composites was studied .The results show that as the CVI C/C-SiC intermediate composites' density increases ,the residual C content increases and residual Si content decreases in the CVI-GSI C/C-SiC composites ,the SiC content increases first and then decrea-ses ,and the density of CVI-GSI C/C-SiC composites increases first and then decreases;as the CVI C/C-SiC in termediate composites' density is increased from 1 .27g/cm3 to 1 .63g/cm3 ,the mechanical properties of CVI-GSI C/C-SiC composites increase at first ,which then decrease with the further in-creasing of CVI-C/C-SiC composites' density .Specifically ,when the CVI C/C-SiC composites density is 1 .42g/cm3 ,the prepared CVI-GSI C/C-SiC composites has the best mechanical properties ,with flexure strength ,flexure modulus and fracture toughness of 247 .50MPa ,25 .63GPa and 10 .08MPa · m1/2 , respectively .%采用密度為1.0g/cm3的C/C素坯,聯(lián)合化學氣相滲透(CVI)和氣相滲硅(GSI)2種工藝制備C/C-SiC復合材料,研究CVI C/C-SiC復合材料中間體的密度對CVI-GSI C/C-SiC復合材料物相組成、微觀結(jié)構(gòu)及力學性能的影響.結(jié)果表明:隨著CVI C/C-SiC復合材料中間體密度的增大,CVI-GSI C/C-SiC復合材料C含量增多,殘余Si含量減少,SiC含量先增多后減少,CVI-GSI C/C-SiC復合材料的密度先增大后減小;隨著CVI C/C-SiC復合材料中間體的密度由1.27g/cm3增加到1.63g/cm3時,得到的CVI-GSI C/C-SiC復合材料的力學性能先升高后降低.當CVI C/C-SiC復合材料密度為1.42g/cm3時,制得的CVI-GSI C/C-SiC復合材料力學性能最好,其彎曲強度為247.50M Pa,彎曲模量為25.63GPa,斷裂韌度為10.08MPa·m1/2.
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