不同物相电沉积CNTs对C/SiC复合材料力学性能的影响

采用电沉积法与化学气相渗透(CVI)法将碳纳米管(CNTs)分别引入到碳纤维表面和SiC基体中,制得了不同物相电沉积CNTs的C/SiC复合材料(CNTs-C)/SiC和C/(CNTs-SiC)。研究了CNTs沉积物相对C/SiC复合材料力学性能的影响,分析了不同CNTs沉积物相的C/SiC复合材料的拉伸强度及断裂机制。结果表明:相较于未加CNTs的C/SiC复合材料,CNTs沉积到碳纤维表面的(CNTs-C)/SiC复合材料的拉伸强度提高了67.3%,断裂功提高了107.2%;而将CNTs引入到SiC基体中的C/(CNTs-SiC)复合材料的断裂功有所降低,拉伸强度也仅提高了6.9%,CNTs没有表现出明显的增强增韧效果;C/(CNTs-SiC)复合材料与传统的C/SiC复合材料有相似的断裂形貌特征,断裂拔出机制类似,主要为纤维增强增韧,CNTs的作用不明显。

Effect of CNTs deposited at different phases on mechanical properties of C/SiC composites

Carbon nanotubes (CNTs) were introduced into carbon fiber surface and SiC matrix through electrodeposition and chemical vapor infiltration (CVI) method. Then the C/SiC composites (CNTs-C)/SiC and C/(CNTs-SiC) with CNTs deposited at different phases were obtained. The effects of CNTs deposition phases on the mechanical properties of C/SiC composites were investigated. The tensile strength and fracture mechanisms of C/SiC composites with CNTs deposited at different phases were studied. The results show that compared with C/SiC composite without the addition of CNTs, the tensile strength of (CNTs-C)/SiC composites with CNTs deposited on the surface of carbon fibers increases by 67.3%, and the work of fracture increases by 107.2%. However, the work of fracture of C/(CNTs-SiC) composites which introducing CNTs into the SiC matrix decreases, and the tensile strength only increases by 6.9%, the CNTs does not show significant strengthening and toughening effects. C/(CNTs-SiC) composites have the similar fracture morphology characteristics of traditional C/SiC composites, and both of them have the similar fracture and pullout mechanisms, mostly for carbon fiber strengthening and toughening, and CNTs does not play a significant role.