1.1 本规程涵盖了在单轴加载应变控制条件下材料热机械疲劳（TMF）性能的测定。“热机械”疲劳循环在这里被定义为试样量规截面上的均匀温度和应变场为 同时变化和独立控制 本规程旨在解决为支持材料研发、机械设计、工艺和质量控制、产品性能和故障分析等活动而进行的TMF测试。 虽然这种做法是针对应变控制测试的，但许多章节将为力控制或应力控制的TMF测试提供有用的信息。 1.2 这种做法允许温度和机械应变的任何最大值和最小值，以及温度-机械应变相位，限制条件是这些参数在整个测试期间保持循环恒定。对压力、湿度、环境介质等环境因素没有限制，只要它们在整个测试过程中得到控制，不会及时导致试样尺寸的损失或变化，并在数据报告中详细说明。 1.3 这种做法的使用仅限于试样，不包括全尺寸组件、结构或消费品的测试。 1.4 以国际单位制表示的值应被视为标准值。本标准不包括其他计量单位。 1.5 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。 =====意义和用途====== 4.1 在高温环境中使用结构材料时，易受疲劳损伤的部件可能会经历某种形式的 同时变化 在整个给定循环中的热力和机械力。这些条件通常是关键问题，因为它们结合了温度依赖和循环依赖（疲劳）损伤机制，其严重程度与循环温度和循环机械应变之间的相位关系有关。 可以发现，这些效应会影响微观结构的演变、降解的微观机制以及最终影响循环寿命的各种其他现象学过程。应变控制的热机械疲劳试验通常用于研究在理想条件下同时变化的热载荷和机械载荷的影响，其中循环的理论上均匀的温度和应变场在整个试样的应变计部分受到外部施加和控制。

1.1 This practice covers the determination of thermomechanical fatigue (TMF) properties of materials under uniaxially loaded strain-controlled conditions. A “thermomechanical” fatigue cycle is here defined as a condition where uniform temperature and strain fields over the specimen gage section are simultaneously varied and independently controlled . This practice is intended to address TMF testing performed in support of such activities as materials research and development, mechanical design, process and quality control, product performance, and failure analysis. While this practice is specific to strain-controlled testing, many sections will provide useful information for force-controlled or stress-controlled TMF testing. 1.2 This practice allows for any maximum and minimum values of temperature and mechanical strain, and temperature-mechanical strain phasing, with the restriction being that such parameters remain cyclically constant throughout the duration of the test. No restrictions are placed on environmental factors such as pressure, humidity, environmental medium, and others, provided that they are controlled throughout the test, do not cause loss of or change in specimen dimensions in time, and are detailed in the data report. 1.3 The use of this practice is limited to specimens and does not cover testing of full-scale components, structures, or consumer products. 1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 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 In the utilization of structural materials in elevated temperature environments, components that are susceptible to fatigue damage may experience some form of simultaneously varying thermal and mechanical forces throughout a given cycle. These conditions are often of critical concern because they combine temperature dependent and cycle dependent (fatigue) damage mechanisms with varying severity relating to the phase relationship between cyclic temperature and cyclic mechanical strain. Such effects can be found to influence the evolution of microstructure, micromechanisms of degradation, and a variety of other phenomenological processes that ultimately affect cyclic life. The strain-controlled thermomechanical fatigue test is often used to investigate the effects of simultaneously varying thermal and mechanical loadings under idealized conditions, where cyclic theoretically uniform temperature and strain fields are externally imposed and controlled throughout the gage section of the specimen.