摘要
连续碳化硅纤维增强碳化硅复合材料(SiC_(f)/SiC)在中温(500~1000℃)范围内会发生蠕变断裂时间显著缩短的脆化现象,其机制主要与界面的微观结构和力学性能有关。为此,本文开展了国产二代平纹编织SiC_(f)/SiC(2D-SiC_(f)/SiC)复合材料在中温范围的蠕变脆化失效机制研究。采用TEM分析了中温下不同蠕变条件后2D-SiC_(f)/SiC的界面微观结构,进一步利用微纳力学测试技术表征界面力学性能。结果表明:纤维/界面侧在500℃下出现多孔隙的富碳层;800℃时,界面出现自发氧化,同时SiO2填充了部分氮化硼(BN)界面因氧化消耗后产生的空隙。当温度进一步升高至1000℃后,氧元素主要分布于纤维/基体一侧。2D-SiC_(f)/SiC的中温脆化机制与界面结合状态高度相关,蠕变断裂时间与界面结合的强弱呈现明显的反比关系,表明过强的界面结合不能发挥界面脱粘、纤维拔出等相关增韧机制,此时裂纹直接贯穿纤维,显著缩短其中温蠕变断裂时间。
The creep rupture time of continuous silicon carbide fiber reinforced silicon carbide composite(SiC_(f)/SiC)is shortened at intermediate temperature(500-1000℃)inevitably,known as creep embrittlement.The mechanism primarily depends on the microstructure and the interfacial bonding state of the fiber/matrix interface.Therefore,present work investigated the creep embrittlement mechanisms of the domestic 2nd-generation plain woven SiC_(f)/SiC(2D-SiC_(f)/SiC)under intermediate temperature.The interfacial microstructure evolution and mechanical properties was characterized by transmission electron microscopy(TEM)and micro-mechanical testing techniques respectively.The results indicate that a carbon-rich layer with pores appear on the fiber/interface side at 500℃.Spontaneous oxidation of the interface occurs at 800℃,while a thin SiO2 layer fills the gap generated at the BN interface due to oxidation.When the temperature increases to 1000℃,oxygen elements are mainly distributed on the fiber/matrix side.The intermediate temperature embrittlement mechanism of 2D-SiC_(f)/SiC is closely associated with interface bonding state.The creep rupture time shows a clear inverse relationship with the interface bonding state,indicating that excessively strong interface bonding hinders related toughening mechanisms such as interface debonding and fiber pullout.Consequently,cracks directly penetrate the fiber,shortening the creep rupture time significantly.
作者
陈乐
管皞阳
朱思雨
王佳璇
唐睿
何宗倍
张程煜
CHEN Le;GUAN Haoyang;ZHU Siyu;WANG Jiaxuan;TANG Rui;HE Zongbei;ZHANG Chengyu(Science and Technology on Reactor Fuel and Materials Laboratory,Nuclear Power Institute of China,Chengdu 610213,China;Key Laboratory of Ultra-high Temperature Structural Composites,Northwestern Polytechnical University,Xi'an 710072,China;AVIC Research Institute for Special Structures of Aeronautical Composites,Jinan 250023,China)
出处
《复合材料学报》
北大核心
2025年第6期3513-3520,共8页
Acta Materiae Compositae Sinica
基金
国家自然科学基金(U2241239)
国防科技基础加强计划(2023-JCJQ-LB-071)。
