1.1 本规程涵盖了在环境温度下测定先进陶瓷的恒定振幅、轴向、拉伸循环疲劳行为和性能，以建立“基线”循环疲劳性能。本规程基于在环境温度下对高级陶瓷进行拉伸测试的经验和现有标准，并解决了各种建议的试样几何形状、试样制造方法、测试模式（力、位移或应变控制）、测试速率和频率、允许弯曲以及数据收集和报告程序。 本规程不适用于部件或零件（即具有不均匀或多轴应力状态的机械元件）的轴向循环疲劳试验。 1.2 本规程主要适用于宏观上表现出各向同性、均匀、连续行为的高级陶瓷。虽然本实践主要适用于整体高级陶瓷，但某些晶须或颗粒增强复合陶瓷以及某些不连续纤维增强复合陶瓷也可能满足这些宏观行为假设。 一般来说，连续纤维增强陶瓷复合材料（CFCC）在宏观上不会表现出各向同性、均匀、连续的行为，不建议将此做法应用于这些材料。 1.3 以国际单位制表示的数值应视为标准，并符合 IEEE/ASTM 硅 10 . 1.4 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、健康和环境实践，并确定监管限制的适用性。 请参阅第节 7. 具体预防措施。 1.5 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 4.1 本规程可用于材料开发、材料比较、质量保证、表征、可靠性评估和设计数据生成。 4.2 高强度、整体式高级陶瓷材料通常具有较小的晶粒尺寸（<50μm）和接近理论密度的体积密度。这些材料是需要高耐磨性、耐腐蚀性和高温强度的承重结构应用的候选材料。尽管弯曲试验方法通常用于评估高级陶瓷的强度，但弯曲试样中的不均匀应力分布限制了材料在断裂时承受最大外加应力的体积。 单轴加载拉伸强度试验可以提供更多均匀应力材料的强度极限缺陷信息。 4.3 循环疲劳本质上是一种概率现象，如STP 91A和STP 588所述 ( 1. , 2. ) . 4. 此外，高级陶瓷的强度本质上是概率的。因此，统计分析和设计需要在每个测试条件下有足够数量的试样，STP 91A中提供了足够数量的指南 ( 1. ) ，STP 588 ( 2. ) ，并练习 E739 . 由于试样标距段中材料的体积或表面积不同，可用于循环疲劳试验的许多不同拉伸试样几何形状可能会导致特定材料的测量循环疲劳行为发生变化。 4.4 拉伸循环疲劳试验提供了波动单轴拉伸应力下材料响应的信息。需要均匀应力状态来有效评估任何非线性应力- 累积损伤过程（例如，微裂纹、循环疲劳裂纹扩展等）可能导致的应变行为。 4.5 循环疲劳引起的累积损伤过程可能受到测试模式、测试速率（与频率相关）、最大和最小力之间的差异的影响( R 或Α），加工或组成材料组合的影响，或环境影响，或两者兼而有之。影响循环疲劳行为的其他因素包括:孔隙或孔隙度含量、试样制备或制造方法、试样调节、试验环境、循环期间的力或应变极限、波形（即正弦、梯形等）。 )和故障模式。其中一些影响可能是难以量化的应力腐蚀或亚临界（缓慢）裂纹扩展的后果。此外，试样制造过程（机加工）产生的表面或近表面缺陷可能无法通过表面纹理的常规测量进行量化。因此，表面效应（例如，反映在Marin分类的循环疲劳折减系数中） ( 3. ) )必须从使用具有相同制造历史的试样进行的多次循环疲劳试验的结果中推断。 4.6 从特定材料或零件的选定部分或两者中按标准尺寸制造的试样的循环疲劳试验结果可能不能完全代表整个全尺寸最终产品的循环疲劳行为或其在不同环境中的使用行为。 4.7 然而，出于质量控制目的，从标准拉伸试样得出的结果可被视为指示在给定的主要加工条件和后处理条件下从中获取的材料的响应- 加工热处理。 4.8 高级陶瓷的循环疲劳行为取决于其固有的抗断裂能力、缺陷的存在或损伤累积过程，或两者兼而有之。在没有任何视觉证据（如宏观裂纹）的情况下，试样中可能存在重大损伤。这可能导致刚度和保持强度的特定损失。根据进行试验的目的，而不是最终断裂，刚度或保持强度的特定损失可能构成故障。 在发生断裂的情况下，建议对断裂表面和断口进行分析，尽管这超出了本规程的范围。

1.1 This practice covers the determination of constant-amplitude, axial, tension-tension cyclic fatigue behavior and performance of advanced ceramics at ambient temperatures to establish “baseline” cyclic fatigue performance. This practice builds on experience and existing standards in tensile testing advanced ceramics at ambient temperatures and addresses various suggested test specimen geometries, test specimen fabrication methods, testing modes (force, displacement, or strain control), testing rates and frequencies, allowable bending, and procedures for data collection and reporting. This practice does not apply to axial cyclic fatigue tests of components or parts (that is, machine elements with nonuniform or multiaxial stress states). 1.2 This practice applies primarily to advanced ceramics that macroscopically exhibit isotropic, homogeneous, continuous behavior. While this practice applies primarily to monolithic advanced ceramics, certain whisker- or particle-reinforced composite ceramics, as well as certain discontinuous fibre-reinforced composite ceramics, may also meet these macroscopic behavior assumptions. Generally, continuous fibre-reinforced ceramic composites (CFCCs) do not macroscopically exhibit isotropic, homogeneous, continuous behavior and application of this practice to these materials is not recommended. 1.3 The values stated in SI units are to be regarded as the standard and are in accordance with IEEE/ASTM SI 10 . 1.4 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Refer to Section 7 for specific precautions. 1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 4.1 This practice may be used for material development, material comparison, quality assurance, characterization, reliability assessment, and design data generation. 4.2 High-strength, monolithic advanced ceramic materials are generally characterized by small grain sizes (<50 μm) and bulk densities near the theoretical density. These materials are candidates for load-bearing structural applications requiring high degrees of wear and corrosion resistance, and high-temperature strength. Although flexural test methods are commonly used to evaluate strength of advanced ceramics, the nonuniform stress distribution in a flexure specimen limits the volume of material subjected to the maximum applied stress at fracture. Uniaxially loaded tensile strength tests may provide information on strength-limiting flaws from a greater volume of uniformly stressed material. 4.3 Cyclic fatigue by its nature is a probabilistic phenomenon as discussed in STP 91A and STP 588 ( 1 , 2 ) . 4 In addition, the strengths of advanced ceramics are probabilistic in nature. Therefore, a sufficient number of test specimens at each testing condition is required for statistical analysis and design, with guidelines for sufficient numbers provided in STP 91A ( 1 ) , STP 588 ( 2 ) , and Practice E739 . The many different tensile specimen geometries available for cyclic fatigue testing may result in variations in the measured cyclic fatigue behavior of a particular material due to differences in the volume or surface area of material in the gage section of the test specimens. 4.4 Tensile cyclic fatigue tests provide information on the material response under fluctuating uniaxial tensile stresses. Uniform stress states are required to effectively evaluate any nonlinear stress-strain behavior which may develop as the result of cumulative damage processes (for example, microcracking, cyclic fatigue crack growth, etc.). 4.5 Cumulative damage processes due to cyclic fatigue may be influenced by testing mode, testing rate (related to frequency), differences between maximum and minimum force ( R or Α), effects of processing or combinations of constituent materials, or environmental influences, or both. Other factors that influence cyclic fatigue behavior are: void or porosity content, methods of test specimen preparation or fabrication,test specimen conditioning, test environment, force or strain limits during cycling, wave shapes (that is, sinusoidal, trapezoidal, etc.), and failure mode. Some of these effects may be consequences of stress corrosion or sub-critical (slow) crack growth which can be difficult to quantify. In addition, surface or near-surface flaws introduced by the test specimen fabrication process (machining) may or may not be quantifiable by conventional measurements of surface texture. Therefore, surface effects (for example, as reflected in cyclic fatigue reduction factors as classified by Marin ( 3 ) ) must be inferred from the results of numerous cyclic fatigue tests performed with test specimens having identical fabrication histories. 4.6 The results of cyclic fatigue tests of specimens fabricated to standardized dimensions from a particular material or selected portions of a part, or both, may not totally represent the cyclic fatigue behavior of the entire full-size end product or its in-service behavior in different environments. 4.7 However, for quality control purposes, results derived from standardized tensile test specimens may be considered indicative of the response of the material from which they were taken for given primary processing conditions and post-processing heat treatments. 4.8 The cyclic fatigue behavior of an advanced ceramic is dependent on its inherent resistance to fracture, the presence of flaws, or damage accumulation processes, or both. There can be significant damage in the test specimen without any visual evidence such as the occurrence of a macroscopic crack. This can result in a specific loss of stiffness and retained strength. Depending on the purpose for which the test is being conducted, rather than final fracture, a specific loss in stiffness or retained strength may constitute failure. In cases where fracture occurs, analysis of fracture surfaces and fractography, though beyond the scope of this practice, are recommended.