通过单向拉伸试验，对比研究平纹叠层SiC/SiC复合材料在室温和高温(1200℃)环境下的宏观力学特性，并采用扫描电镜对试验件断口进行观测，以分析其微观损伤模式和破坏机理.结果表明：平纹叠层SiC/SiC复合材料的室温和高温拉伸应力-应变行为均表现为非线性特征，具有较高的轴向拉伸基体开裂应力；两者拉伸强度相差不大，但高温下的断裂应变比室温下的高.从宏观断口分析可知，两者均呈现韧性断裂，但纤维拔出长度和断口平齐程度有所不同.材料内部产生的基体裂纹大部分与加载方向垂直；断面上经向纤维束发生纵向拉伸断裂破坏，内部存在严重的界面脱粘损伤以及纬向纤维束发生轴向劈裂破坏是材料在室温和高温下的拉伸破坏机理.高温下由于纤维与基体间的界面层在一定程度上被高温氧化而退化失效，使界面结合变弱和界面滑移力降低，从而产生较长的纤维拔出长度，所以高温下材料具有较高的断裂韧性.
Monotonic tensile experiments at room temperature and 1200℃ were performed to investigate the mechanical behaviour of 2D-SiC/SiC composites. The microstructures of specimens were observed by using scanning electron microscope to analyse the damage modes and failure mechanisms. The results indicate that the stress-strain responses of 2D-SiC/SiC composites under tensile loading at both room temperature and 1200℃ are bi-linear and damage appears at the high stress level. Their tensile strengths are fairly close, but the fracture strain at 1200℃ is higher than that at room temperature. Specimens at both room and high temperature demonstrate ductile behaviour, but their pullout length of fibre and smoothness of fracture surfaces are different. Transverse matrix cracking, longitudinal tensile fractures of warp tows with serious interface debonding, and axial splitting failure of weft tows with intact fibres are the main damage mechanisms. The high temperature oxidation was found to have an influence on the properties of fibre-matrix interface of 2D-SiC/SiC composites. The weak interface and decrease of interfacial sliding stress result in the longer pullout length of fibre at 1200℃ in the oxidation environment, and therefore, 2D-SiC/SiC composites has high fracture toughness at 1200℃.
［1］张立同, 成来飞. 连续纤维增韧陶瓷基复合材料可持续发展战略探讨［J］. 复合材料学报, 2007, 24(2): 1-6.
ZHANG Litong, CHENG Laifei. Discussion on strategies of sustainable development of continuous fiber reinforced ceramic matrix composites［J］. Acta Materiae Compositae Sinica, 2007, 24(2): 1-6.
［2］高铁, 洪智亮, 杨娟. 商用航空发动机陶瓷基复合材料部件的研发应用及展望［J］. 航空制造技术, 2014, 6: 14-21.
GAO Tie, HONG Zhiliang, YANG Juan. Application and prospect of ceramic matrix composite components for commercial aircraft engine［J］. Aeronautical Manufacturing Technology, 2014, 6: 14-21.
［3］杨成鹏, 矫桂琼, 王波. 2D-C/SiC复合材料的单轴拉伸力学行为及其强度［J］. 力学学报, 2011, 43(2): 330-337.
YANG Chengpeng, JIAO Guiqiong, WANG Bo. Uniaxial tensile stress-strain behavior and strength of plain woven C/SiC composite［J］. Chinese Journal of Theoretical and Applied Mechanics, 2011, 43(2): 330-337.
［4］管国阳, 矫桂琼, 张增光. 2D-C/Si复合材料的宏观拉压特性和失效模式［J］. 复合材料学报, 2005, 22(4): 81-85.
GUAN Guoyang, JIAO Guiqiong, ZHANG Zengguang. Uniaxial macro-mechanical property and failure mode of a 2D-woven C/SiC composite［J］. Acta Materiae Compositae Sinica, 2005, 22(4): 81-85.
［5］梅辉, 成来飞, 张立同, 等. 2维C/SiC复合材料的拉伸损伤演变过程和微观结构特征［J］. 硅酸盐学报, 2007, 35(2): 137-143.
MEI Hui, CHENG Laifei, ZHANG Litong, et al. Damage evolution and microstructural characterization of a cross-woven C/SiC composite under tensile loading［J］. Journal of the Chinese Ceramic Society, 2007, 35(2): 137-143.
［6］郭洪宝, 王波, 贾普荣, 等. 平纹编织陶瓷基复合材料面内剪切细观损伤行为研究［J］. 力学学报, 2016, 48(2): 361-368.
GUO Hongbao, WANG Bo, JIA Purong, et al. Mesoscopic damage behaviors of plain woven ceramic composite under in-plane shear loading［J］. Chinese Journal of Theoretical and Applied Mechanics, 2016, 48(2): 361-368.
［7］BERNACHY-BARBE F, GLBART L, BORNERT M, et al. Anisotropic damage behaviour of SiC/SiC composite tubes: Multiaxial testing and damage characterization［J］. Composites: Part A, 2015, 76: 281-288.
［8］HAYHURST D R, LECKIE F A, EVANS A G. Component design-based model for deformation and rupture of tough fibre-reinforced ceramic matrix composites［J］. Proceedings of the Royal Society A, 1991, 434(1891): 369-381.
［9］TANG C, BLACKLOCK M, HAYHURST D R. Uni-axial stress-strain response and thermal conductivity degradation of ceramic matrix composite fibre tows［J］. Proceedings of the Royal Society A, 2009, 465(2109): 2849-2876.
［10］TANG C, HAYHURST D R. Predictions of thermo-mechanical behaviour of a Nicalon-CAS 0°—90° ceramic matrix composite from constituent materials properties［J］. Journal of Composite Materials, 2011, 45(12): 1337-1350.
［11］TANG C, BLACKLOCK M, HAYHURST D R. Stress-strain response and thermal conductivity degradation of ceramic matrix composite fiber tows in 0°—90° uni-directional and woven composites［J］. Journal of Composite Materials, 2011, 45(14): 1461-1482.
［12］CHABOCHE J L, LESNE P M, MAIRE J F. Continuum damage mechanics, anisotropy and damage deactivation for brittle materials like concrete and ceramic composites［J］. International Journal of Damage Mechanics, 1995, 4(1): 5-22.
［13］MAIRE J F, CHABOCHE J L. A new formulation of continuum damage mechanics (CDM) for composite materials［J］. Aerospace Science and Technology, 1997, 1(4): 247-257.
［14］CHABOCHE J L, MAIRE J F. New progress in micromechanics-based CDM models and their application to CMCs［J］. Composites Science and Technology, 2001, 61(15): 2239-2246.
［15］CAMUS G. Modelling of the mechanical behavior and damage processes of fibrous ceramic matrix composites: Application to a 2-D SiC/SiC［J］. International Journal of Solids and Structures, 2000, 37(6): 919-942.
［16］RAJAN V P, SHAW J H, ROSSOL M N, et al. An elastic-plastic constitutive model for ceramic composite laminates［J］. Composites Part A: Applied Science and Manufacturing, 2014, 66: 44-57.
［17］ASTM. Standard test method for monotonic tensile behavior of continuous fiber-reinforced advanced ceramics with solid rectangular cross-section test specimens at ambient temperature: ASTM C1275-16［S］. Philadelphia, USA: ASTM International, 2000.
［18］ASTM. Standard test method for monotonic tensile strength testing of continuous fiber-reinforced advanced ceramics with solid rectangular cross-section test specimens at elevated temperatures: ASTM C1359-13［S］. Philadelphia, USA: ASTM International, 2000.
［19］MEI Hui, BAI Qianglai, LI Haiqing, et al. Effect of loading rate and temperature on monotonic tensile behavior in two-dimensional C/SiC composites［J］. Ceramics International, 2014, 40(10): 16635-16640.
［20］VAGAGINI E, DOMERGUE J, EVANS A. Relationships between hysteresis measurements and the constituent properties of ceramic matrix composites: I. Theory［J］. Journal of the American Ceramic Society, 1995, 78(10): 2709-2720.
［21］王锟, 陈刘定, 郑翔. 平纹编织C/SiC复合材料在室温和高温环境下的拉伸行为［J］. 航空材料学报, 2010, 30(1): 78-84.
WANG Kun, CHEN Liuding, ZHENG Xiang. Comparison of tensile behavior of plain-woven carbon/silicon carbide composites at room temperature and high temperature［J］. Journal of Aeronautical Materials, 2010, 30(1): 78-84.
［22］REBILLAT F, GUETTE A, ESPITALIER L. Oxidation resistance of SiC/SiC micro and minicomposites with a highly crystallised BN interphase［J］. Journal of the European Ceramic Society, 1998, 18(13): 1809-1819.
［23］YANG Chengpeng, JIAO Guiqiong, WANG Bo, et al. Mechanical degradation mechanisms of 2D-C/SiC composites: Influence of preloading and oxidation［J］. Journal of the European Ceramic Society, 2015, 35(10): 2765-2773.
［24］吴守军. 3D SiC/SiC复合材料热化学环境行为［D］. 西安: 西北工业大学, 2006.
WU Shoujun. Themochemical environmental behaviors of 3D SiC/SiC composite［D］. Xi’an: Northwestern Polytechnical University, 2006.
