1.1 本规程适用于脆性材料中断裂镜尺寸的分析和解释。断裂反射镜( 图1 )是脆性材料中围绕断裂起源的断裂标记。断裂镜像尺寸可与已知的断裂镜像常数一起使用，以估计断裂部件中的应力。或者，可以将断裂镜尺寸与试样中的已知应力结合使用，以计算断裂镜常数。本规程适用于玻璃和多晶陶瓷实验室试样以及断裂部件。 玻璃和陶瓷的分析和解释程序相似，但不完全相同。列出并描述了不同的光学显微镜检查技术，包括观察角度、照明方法、适当的放大倍数和测量协议。给出了计算断裂反射镜常数和解释圆形和非圆形反射镜的断裂反射镜尺寸和形状的指南，包括应力梯度、几何效应和/或残余应力。 本规程提供了图形和显微照片，说明了玻璃和多晶陶瓷断裂镜中常见的不同类型特征和测量技术。 注1: 初始缺陷可能会稳定增长至尺寸a c 在应力强度达到K时发生不稳定断裂之前 集成电路 . 后视镜雾半径为R 一、 ，雾迹半径为R o ，分支距离为R b . 这些跃迁对应于镜像常数A 一、 A. o ，和 b 分别地 1.2 以国际单位制表示的数值应视为标准值。本标准不包括其他计量单位。 1.3 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全和健康实践，并确定监管限制的适用性。 ====意义和用途====== 5.1 断口镜尺寸分析是分析玻璃和陶瓷断口的有力工具。 断裂反射镜是脆性材料中的断裂标志，如实践中所讨论的，围绕断裂起源 C1256 和 C1322 . 图1 显示了已识别关键特征的示意图。 图2 以玻璃为例。断裂反射镜区域非常平滑，在玻璃中具有高反射性，因此被称为“断裂反射镜”事实上，高倍显微镜显示，即使在玻璃的镜面区域内，随着裂纹远离原点，也有非常精细的特征和逐渐增加的粗糙度。 这些是亚微米大小，因此无法用光学显微镜识别。早期的研究者将断裂镜解释为具有离散边界，包括玻璃中的“镜像-雾”边界和“雾-黑客”边界。这些边界也分别被称为“内镜像”或“外镜像”边界。现在已知，不存在对应于断口特征中特定变化的离散边界。表面粗糙度从裂缝反射镜内逐渐增加到明显边界以外。 边界是一个解释、显微镜的分辨率和观察模式的问题。在非常弱的样本中，反射镜可能比样本或组件大，并且不会出现边界。 σ = 原点应力（MPa或ksi）， R = 断裂镜半径（m或in）， A. = 断裂镜像常数（MPa√m或ksi√中）。 等式1 以下简称为“经验应力-断裂镜像尺寸关系”或“应力镜像尺寸关系”。 历史回顾 等式1 和一般的断裂镜分析，可在参考文献中找到 1. 和 2. . 5.5 A、 “断裂镜像常数”（有时也称为“镜像常数”）具有应力强度单位（MPa）√m或ksi√在）中，许多人认为这是一种物质属性。如所示 无花果。1和 2. ，可以在眼镜中辨别出单独的雾状和锯齿状区域以及它们之间的明显边界。每个都有一个对应的镜像常数a。最常见的符号是指镜像- 雾边界作为内镜像边界，其镜像常数指定为A 一、 . 雾线边界称为外镜像边界，其镜像常数指定为A o . 在多晶陶瓷中，通常看不到镜雾边界。通常，仅测量镜像黑客边界，并且仅测量A o 对于镜像，计算了哈克尔边界。一种比 等式1 可能基于应力强度因子（K 我 )对着镜子- 雾或雾划破边界，但 等式1 更实用，使用更简单。 5.6 尺寸预测基于 等式1 A值或应力强度因子与拉伸试样中小反射镜的极限情况非常匹配。这也适用于以强弯曲试样中的表面缺陷为中心的小半圆镜。因此，至少对于一些特殊的反射镜情况，A应该与基于应力强度因子的更基本参数直接相关。 5.7 实验室试样断口中断口反射镜的尺寸可与已知的断口反射镜常数结合使用，以验证断口处的应力是否符合预期。实验室试样的断裂镜尺寸和已知应力也可用于计算断裂镜常数A。 5.8 部件中断裂反射镜的尺寸可与已知断裂反射镜常数结合使用，以估计部件在原点处的应力。实践 C1322 有各种陶瓷和玻璃的断裂镜常数的综合列表。

1.1 This practice pertains to the analysis and interpretation of fracture mirror sizes in brittle materials. Fracture mirrors ( Fig. 1 ) are telltale fractographic markings that surround a fracture origin in brittle materials. The fracture mirror size may be used with known fracture mirror constants to estimate the stress in a fractured component. Alternatively, the fracture mirror size may be used in conjunction with known stresses in test specimens to calculate fracture mirror constants. The practice is applicable to glasses and polycrystalline ceramic laboratory test specimens as well as fractured components. The analysis and interpretation procedures for glasses and ceramics are similar, but they are not identical. Different optical microscopy examination techniques are listed and described, including observation angles, illumination methods, appropriate magnification, and measurement protocols. Guidance is given for calculating a fracture mirror constant and for interpreting the fracture mirror size and shape for both circular and noncircular mirrors including stress gradients, geometrical effects, and/or residual stresses. The practice provides figures and micrographs illustrating the different types of features commonly observed in and measurement techniques used for the fracture mirrors of glasses and polycrystalline ceramics. Note 1: The initial flaw may grow stably to size a c prior to unstable fracture when the stress intensity reaches K Ic . The mirror-mist radius is R i , the mist-hackle radius is R o , and the branching distance is R b . These transitions correspond to the mirror constants, A i , A o , and A b , respectively. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. ====== Significance And Use ====== 5.1 Fracture mirror size analysis is a powerful tool for analyzing glass and ceramic fractures. Fracture mirrors are telltale fractographic markings in brittle materials that surround a fracture origin as discussed in Practices C1256 and C1322 . Fig. 1 shows a schematic with key features identified. Fig. 2 shows an example in glass. The fracture mirror region is very smooth and highly reflective in glasses, hence the name “fracture mirror.” In fact, high magnification microscopy reveals that, even within the mirror region in glasses, there are very fine features and escalating roughness as the crack advances away from the origin. These are submicrometer in size and hence are not discernable with an optical microscope. Early investigators interpreted fracture mirrors as having discrete boundaries including a “mirror-mist” boundary and also a “mist-hackle” boundary in glasses. These were also termed “inner mirror” or “outer mirror” boundaries, respectively. It is now known that there are no discrete boundaries corresponding to specific changes in the fractographic features. Surface roughness increases gradually from well within the fracture mirror to beyond the apparent boundaries. The boundaries were a matter of interpretation, the resolving power of the microscope, and the mode of viewing. In very weak specimens, the mirror may be larger than the specimen or component and the boundaries will not be present. σ = stress at the origin (MPa or ksi), R = fracture mirror radius (m or in), A = fracture mirror constant (MPa√m or ksi√in). Eq 1 is hereafter referred to as the “empirical stress – fracture mirror size relationship,” or “stress-mirror size relationship” for short. A review of the history of Eq 1 , and fracture mirror analysis in general, may be found in Refs 1 and 2 . 5.5 A, the “fracture mirror constant” (sometimes also known as the “mirror constant”) has units of stress intensity (MPa√m or ksi√in) and is considered by many to be a material property. As shown in Figs. 1 and 2 , it is possible to discern separate mist and hackle regions and the apparent boundaries between them in glasses. Each has a corresponding mirror constant, A. The most common notation is to refer to the mirror-mist boundary as the inner mirror boundary, and its mirror constant is designated A i . The mist-hackle boundary is referred to as the outer mirror boundary, and its mirror constant is designated A o . The mirror-mist boundary is usually not perceivable in polycrystalline ceramics. Usually, only the mirror-hackle boundary is measured and only an A o for the mirror-hackle boundary is calculated. A more fundamental relationship than Eq 1 may be based on the stress intensity factors (K I ) at the mirror-mist or mist-hackle boundaries, but Eq 1 is more practical and simpler to use. 5.6 The size predictions based on Eq 1 and the A values, or alternatively stress intensity factors, match very closely for the limiting cases of small mirrors in tension specimens. This is also true for small semicircular mirrors centered on surface flaws in strong flexure specimens. So, at least for some special mirror cases, A should be directly related to a more fundamental parameter based on stress intensity factors. 5.7 The size of the fracture mirrors in laboratory test specimen fractures may be used in conjunction with known fracture mirror constants to verify the stress at fracture was as expected. The fracture mirror sizes and known stresses from laboratory test specimens may also be used to compute fracture mirror constants, A. 5.8 The size of the fracture mirrors in components may be used in conjunction with known fracture mirror constants to estimate the stress in the component at the origin. Practice C1322 has a comprehensive list of fracture mirror constants for a variety of ceramics and glasses.