Bundle to bundle variation of mean fiber radius for Tyranno® LoxM Si-Ti-C-O fibers
Bundle to bundle variation of mean fiber radius for Tyranno® LoxM Si-Ti-C-O fibers
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Tyranno® LoxM Si-Ti-C-O 纤维的平均纤维半径随束变化
DOI：
10.1023/a:1010912029618
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
T. Ishikawa
中科院分区：
文献类型：
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作者：
I. Davies;T. Ishikawa
基于碳化硅（SiC）系统的陶瓷纤维的持续发展导致了陶瓷基复合材料（CMC）在航空航天领域的众多应用[1，2]。结合适当的表面密封剂以防止氧化，SiC/SiC基复合材料在高达1300 ℃的温度下在空气中显示出优异的抗蠕变性[3]。最近的理论工作[4，5]表明CMC的机械性能主要取决于纤维/基体界面剪切强度τ和纤维强度Weibull参数So和m，这些参数是在复合材料中原位测量的;这已经由作者在真空或空气中在室温和1400 ℃之间测试的SiC/SiC基复合材料的实验证实[6，7]。已知陶瓷纤维失效主要是由于表面缺陷的存在[7，8]，因此，从威布尔标度的角度来看，对于任何给定的纤维长度，纤维强度将是半径r的函数。Lara-Curzio和Ross [9]提出，在计算So和m时，还应考虑纤维半径的任何变化。然而，关于纤维半径沿任何给定纤维[10，11]的长度沿着或相邻纤维之间的变化的研究很少[12]。另一个可能影响复合材料的机械性能的因素是平均纤维半径沿着单个纤维束的长度的变化以及不同纤维束之间的变化。本工作中研究的陶瓷纤维（Tyranno LoxM Si-Ti-CO; Ube Industries Ltd.，Ube City，Japan）通过对单个纤维束的测量确定，具有纤维半径值的归一化高斯分布，平均值ro为4.03 µm，标准差µ为0.60 µm [7]。在目前的工作中，使用扫描电子显微镜（SEM;型号JSM-6300 F，Jeol，东京，日本）的随机选择的纤维束在五个不同的SiC/SiC试样的每一个进行测量。虽然无法确认，但最有可能的情况是，
The continuing development of ceramic fibers based on the silicon carbide (SiC) system has resulted in numerous applications for ceramic matrix composites (CMCs) in the aerospace and space fields [1, 2]. Combined with an appropriate surface sealant to protect against oxidation, SiC/SiC-based composites have shown excellent creep resistance in air at temperatures up to 1300◦ C [3]. Recent theoretical work [4, 5] has indicated that the mechanical properties of CMCs depend mainly on the fiber/matrix interface shear strength, τ, and fiber strength Weibull parameters, So and m, measured in situ the composite; this has been experimentally confirmed by the authors for a SiC/SiC-based composite tested between room temperature and 1400◦ C in either vacuum or air [6, 7]. Ceramic fibers are known to fail chiefly due to the presence of surface flaws [7, 8] and thus, from the point of view of Weibull scaling, the fiber strength will be a function of radius, r, for any given fiber length. Lara-Curzio and Ross [9] have proposed that any variation in fiber radius should also be taken into account when calculating So and m. However, little research exists regarding the variation of fiber radius either along the length of any given fiber [10, 11] or else between neighboring fibers [12]. Another factor that may conceivably affect the mechanical properties of composite materials is the variation in mean fiber radius along the length of a single fiber bundle and also that between different fiber bundles. The aim of the present work is to determine the existence of any significant variation in mean fiber radius between nominally identical fiber bundles for a typical ceramic fiber.The ceramic fiber investigated in the present work (Tyranno LoxM Si-Ti-CO; Ube Industries Ltd., Ube City, Japan) had been determined from measurements within a single fiber bundle to have a normalized Gaussian distribution of fiber radius values with a mean, ro, of 4.03 µm and a standard deviation, µ, of 0.60 µm [7]. In the present work, measurements were made using a scanning electron microscope (SEM; Model JSM-6300F, Jeol, Tokyo, Japan) for a randomly chosen fiber bundle in each of five different SiC/SiC specimens. Although not possible to confirm, the most likely scenario was that each of the fiber bundles