共查询到18条相似文献,搜索用时 62 毫秒
1.
2.
单向Cf/SiC复合材料的弯曲疲劳性能 总被引:2,自引:1,他引:2
对单向Cf/SiC复合材料进行了三点弯曲疲劳性能测试,得到了复合材料的应力-寿命曲线(S-N曲线),并对其进行线性拟合,得到疲劳最大应力与复合材料疲劳寿命的关系;考察了疲劳过程中刚度下降和疲劳裂纹产生情况。结果表明在疲劳过程中复合材料的弯曲模量有3个变化阶段:首先在疲劳加载初期,弯曲模量的下降速度及幅度都较大;其次在弯曲模量下降到原始弯曲模量的85%(133GPa)后,其变化方式没有明显的规律可循,有时甚至可能上升;最后复合材料发生疲劳断裂时,模量将发生突变。显微结构分析表明:基体横向裂纹群的产生是疲劳断裂的独有特征。它的产生是由于基体SiC的断裂应变小于碳纤维的断裂应变,基体首先开裂并导致应力重新分布的结果。 相似文献
3.
4.
5.
为揭示平纹Cf/SiC复合材料的拉伸损伤演化及失效机理,开展了X射线CT原位拉伸试验,获得材料的三维重构图像,利用深度学习的图像分割方法,准确识别出拉伸裂纹并实现其三维可视化。分析了平纹Cf/SiC复合材料损伤演化与失效机理,基于裂纹的三维可视化结果对材料损伤进行了定量表征。结果表明:平纹Cf/SiC复合材料的拉伸力学行为呈现非线性,拉伸过程中主要出现基体开裂、界面脱黏、纤维断裂及纤维拔出等损伤;初始缺陷易引起材料损伤,孔隙多的部位裂纹数量也多;纤维束外基体裂纹可扩展至纤维束内部,并发生裂纹偏转。基于深度学习的智能图像分割方法为定量评估陶瓷基复合材料损伤演化与失效机理提供了有效分析手段。 相似文献
6.
7.
SiC/SiC复合材料及其应用 总被引:1,自引:0,他引:1
李崇俊 《高科技纤维与应用》2013,38(3):1-7
日本开发的Nicalon和Tyranno两种品牌的SiC纤维占有世界上绝对性的市场份额。SiC/SiC复合材料典型的界面层是500 nm厚的单层热解碳(PyC)涂层或多层(PyC-SiC)n涂层,在湿度燃烧环境及中高温条件下界面层的稳定性是应用研究的重点。SiC/SiC复合材料,包括CVI-SiC基体和日本开发的Tyranno hex和NITE-SiC基体等,具有耐高温、耐氧化性和耐辐射性的特点,在航空涡轮发动机部件、航天热结构部件及核聚变反应堆炉第一壁材料等方面正开展工程研制应用。 相似文献
8.
三维编织Cf/SiC复合材料的拉伸破坏行为 总被引:4,自引:6,他引:4
通过三维编织碳纤维(carbon fiber,Cf)/SiC复合材料样品单向拉伸以及单向拉伸加卸载实验.结合样品断口观察.从宏观上分析了三维编织Cf/SiC复合材料单向拉伸时的力学响应,为进一步描述三维编织Cf/SiC复合材料力学行为奠定了实验基础。实验结果表明:三维编织Cf/SiC复合材料单向拉伸时,卸载模量衰减与应力呈线性关系,残余应变的增加与应力呈二次函数关系。微裂纹主要在编织节点处萌生,沿纤维束界面扩展,最终在编织节点处汇合,导致样品发生破坏。 相似文献
9.
电泳沉积-烧结两步法制备C/SiC复合材料 总被引:1,自引:0,他引:1
采用电泳沉积法在石墨基体上制备厚度可控的Si涂层,考察了电泳沉积参数(电压、沉积时间、固含量及添加剂量)对涂层沉积量的影响。所制备的Si涂层通过烧结与石墨基体发生在位反应形成SiC涂层。涂层成分的XRD分析表明烧结后生成β-SiC。用SEM观察涂层烧结前后的形貌,烧结后Si渗入基体内部。孔径分布数据表明所形成的SiC涂层导致石墨孔径变小。1200℃的抗氧化实验表明涂层起到了良好的防护作用。实验提供了一种制备C/SiC复合材料的新方法。 相似文献
10.
11.
12.
《Ceramics International》2022,48(21):31428-31437
A bi-layer oxidation-resistant coating consisting of a mullite outer coating, and a SiC inner coating on the surface of Cf/SiC composites was prepared by the chemical vapour deposition and an air spray sol-gel process, and its corrosion behavior was evaluated in a wet-oxygen coupling environment. Results show that the formation of SiO2 glass layer and its reaction with mullite particles to form aluminosilicate glass layer, leading to an increase in the density of the mullite outer coating, so that the weight loss of bi-layer Mullite/SiC coating coated C/SiC sample was only 1.11 × 10?3 g·cm?2 in the first 100 h of oxidation. However, the weight loss of the coated sample reached 26.82 × 10?3 g·cm?2 after 200 h of oxidation due to a part of the mullite outer coating was detached. The SiO2 glass phase reacted with water vapour to generate gaseous Si(OH)x, which created distinct holes on the surface of the SiO2 glass layer or inside the molten aluminosilicate glass layer. Eventually, the mullite outer coating was blistered and detached from the surface of the sample due to the combination and growth of holes. 相似文献
13.
《Journal of the European Ceramic Society》2020,40(2):290-297
Continuous carbon fiber (Cf) reinforced silicon carbide (SiC) matrix composite (Cf/SiC) was processed through hot pressing (HP) using polycarbosilane (PCS) in matrix and polysilazane in interphase regions as polymer binders. HP experiments were conducted at 4 MPa, 1200 °C and 1 h; followed by PCS polymer impregnation and pyrolysis (PIP) at 1200 °C under vacuum. The BN/SiC-Si3N4 interphase formed on the Cf cloth during BN dispersed polysilazane polymer coating and pyrolysis. The influence of PCS quantity during HP experiments on Cf/SiC composites was studied. Results suggest that sintering of SiC matrix in Cf/SiC composite improves by increasing PCS content during HP; however, high PCS content increases the liquidity of SiC-PCS mixture to flow out of the composite structure. The Cf/SiC composites with relative density ranging from 79 to 83% and flexural strength from 67 to 138 MPa was achieved. 相似文献
14.
Kun Luan Jianjun Liu Baozhong Sun Wei Zhang Jianbao Hu Xiaomeng Fang Chen Ming Erhong Song 《Ceramics International》2019,45(6):6812-6818
Carbon fiber reinforced ceramic owns the properties of lightweight, high fracture toughness, excellent shock resistance, and thus overcomes ceramic's brittleness. The researches on the advanced structure of astronautics, marine have exclusively evaluated the quasi-static mechanical response of carbon fiber reinforced ceramics, while few investigations are available in the open literature regarding elastodynamics. This paper reports the dynamic compressive responses of a carbon fiber reinforced silicon carbide (Cf/SiC) composite (CFCMC) tested by the material test system 801 machine (MTS) and the split Hopkinson pressure bar (SHPB). These tests were to determine the rate dependent compression response and high strain rate failure mechanism of the Cf/SiC composite in in-plane and out-plane directions. The in-plane compressive strain rates are from 0.001 to 2200?s?1, and that of the out-plane direction are from 0.001 to 2400?s?1. The compressive stress-strain curves show the Cf/SiC composite has a property of strain rate sensitivity in both directions while under high strain rate loadings. Its compressive stiffness, compressive stress, and corresponding strain are also strain rate sensitive. The compressive damage morphologies after high strain rate impacting show different failure modes for each loading direction. This study provides knowledge about elastodynamics of fiber-reinforced ceramics and extends their design criterion with a reliable evaluation while applying in the scenario of loading high strain rate. 相似文献
15.
《Ceramics International》2022,48(24):36238-36248
Cf/SiC composite is an excellent structural and functional material, silicon carbide nanowires (SiCnws) are not only a toughening material but also a great application in the field of microwave absorption. In this study, SiCnws are grown on the surface of carbon fiber (Cf) by polymer impregnation and pyrolysis, and the SiC matrix was prepared by chemical vapor osmosis method. The SiCnws are introduced to enhance the mechanical and microwave absorption properties simultaneously. After 3 impregnations, the flexural strength of the composite was 107.35 ± 10 MPa. When the thickness is 1.86 mm, the minimum reflection loss value is ?41.08 dB, and the effective absorption bandwidth (RL ≤ ?10 dB) is 3.86 GHz. Furthermore, the microwave absorption mechanism of the material is discussed. This work provides a new method to prepare lightweight, stable and high-performance microwave absorption materials, and these materials are expected to be used in high temperature environments. 相似文献
16.
Xihui Chen Zhigang Sun Xuming Niu Yingdong Song 《International Journal of Applied Ceramic Technology》2021,18(5):1677-1690
This study presents an in depth analysis over the in situ tensile behavior of Cf/SiC mini composites. As part of the process, the matrix crack spacing at saturation was determined by the in situ x-ray microtomography tensile test and the test results were compared with others obtained by in situ optical microscope tensile test and scanning electron microscopy scan. Moreover, elastic modulus of fiber and matrix as well as interface shear stress were identified by the indirect method and in situ modulus of C fibers and SiC matrix were also measured by the nanoindentation test, showing outcomes much lower than those identified by indirect method. The in situ property parameters measured by in situ XCT tensile test and identified by the indirect method were substituted into the shear-lag model to predict the stress-strain responses of Cf/SiC mini composites and the predicted results agrees well with the experimental data, while there exists large deviation between the stress-strain response predicted by using the in situ modulus of C fibers tested by nanoindentation and the experimental data, which indicates that in situ modulus of C fibers tested by nanoindentation tests cannot be utilized to model the tensile stress-strain responses due to the possible asymmetry of tension and compression of C fibers. 相似文献
17.
《Ceramics International》2020,46(14):22564-22574