精细陶瓷(高级陶瓷, 高级工业陶瓷). 陶瓷复合材料在大气压力和环境温度下的机械性能. 采用缺口灵敏度试验测定抗裂纹扩展能力

[中文适用范围]： 本文件描述了一种根据陶瓷基复合材料 (CMC) 对裂纹扩展的敏感性对其进行分类的方法，该方法通过对不同缺口深度的缺口试样进行拉伸试验来实现。陶瓷基复合材料可分为两类：强度对缺口敏感的材料和强度不受影响的材料。对于敏感性材料，本文件定义了一种确定等效断裂韧性的方法。参数 Keq 定义为均质材料的断裂韧性，该均质材料对裂纹扩展的敏感性与所研究的陶瓷基复合材料相同。Keq 参数的定义使得比较陶瓷基复合材料与其他材料对裂纹扩展的敏感性成为可能。对于缺口不敏感的材料，Keq 的概念不适用。本文件适用于所有沿增强体主轴加载的、具有连续纤维增强的陶瓷基复合材料，包括单向 (1D)、双向 (2D) 和三向 (xD，其中 2 < x ≤ 3)。 [外文原描述]： ISO 18608:2017 describes a method for the classification of ceramic matrix composite (CMC) materials with respect to their sensitivity to crack propagation using tensile tests on notched specimens with different notch depths. Two classes of ceramic matrix composite materials can be distinguished: materials whose strength is sensitive to the presence of notches and materials whose strength is not affected. For sensitive materials, this document defines a method for determining equivalent fracture toughness. The parameter, K eq , is defined as the fracture toughness of a homogeneous material which presents the same sensitivity to crack propagation as the ceramic matrix composite material which is being considered. The definition of the K eq parameter offers the possibility to compare ceramic matrix composite materials with other materials with respect to sensitivity to crack propagation. For notch insensitive materials, the concept of K eq does not apply. ISO 18608:2017 applies to all ceramic matrix composites with a continuous fibre reinforcement, unidirectional (1 D), bidirectional (2 D), and tridirectional (x D, where 2 < x ≤ 3), loaded along one principal axis of reinforcement.