1.1本试验方法包括通过使用在等温条件下承受单轴力的试样，测定与名义均匀材料中的蠕变疲劳变形或裂纹形成有关的机械性能，或同时测定两者。它涉及应变率下的疲劳试验或涉及足够长保持时间的循环，以负责循环变形响应和受蠕变（和氧化）影响的裂纹形成循环。它是一种疲劳测试的测试方法，用于支持材料研发、机械设计、过程和质量控制、产品性能和故障分析等活动。 导致蠕变疲劳变形和开裂的循环条件随材料和给定材料的温度而变化。 1.2本试验方法的使用仅限于试样，不包括全尺寸部件、结构或消费品的试验。 1.3本试验方法的主要目的是提供评估无缺陷工程结构所需的材料特性，该结构包含在足以引起蠕变变形的高温下承受循环载荷的特征。 1.4本试验方法适用于确定恒幅应变控制试验或恒幅力控制试验产生的变形和裂纹形成或形核特性。它主要涉及在力或应变控制下承受单轴载荷的圆棒试样的测试。该程序的重点是在给定循环内同时产生蠕变和疲劳变形及损伤的试验。 它不包括连续产生蠕变和疲劳损伤的块循环试验。在同时产生蠕变疲劳变形和损伤的条件下进行的蠕变疲劳试验可确定的数据包括 （a） 循环应力应变变形响应 （b） 循环蠕变（或松弛）变形响应 （c） 循环硬化、循环软化响应 （d） 在试样中形成单个裂纹或多个裂纹的循环。 注1 — 当裂纹在最初未开裂的试样中形核并扩展至特定尺寸时，即认为裂纹已形成，该尺寸可通过规定的技术检测到。就本标准而言，裂纹的形成通过试样顺应性的可测量增加或通过电位降技术检测到的尺寸来证明。有关如何测量裂纹形成周期的具体细节，请参见 9.5.1 . 1.5本试验方法适用于时间量级- 相关非弹性应变（蠕变）的阶数等于或大于与时间无关的非弹性应变。 注释2 — 术语 非弹性 此处用于指所有非弹性应变。术语 塑料 此处仅指非弹性应变的时间无关（即非蠕变）分量。当应变率超过某个值时，可以获得与时间无关的应变的有用工程估计。例如，1×10的应变率 -3 证券交易委员会 -1 通常用于此目的。该值应随着试验温度的升高而增加。 1.6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。 1.7 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====== 4.1蠕变疲劳试验通常在高温下进行，涉及连续或同时施加必要的载荷条件，以产生由蠕变变形/损伤增强的循环变形/损伤，反之亦然。 除非在真空或惰性环境中进行此类测试，否则氧化也可能导致与损伤累积相关的重要交互作用。蠕变疲劳试验的目的可以是确定以下材料的材料性能数据: （a） 高温下运行的工程结构变形和损伤条件分析的评估输入数据 （b） 本构变形和损伤模型有效性的验证 （c） 材料特性，或 （d） 制定和验证高温部件的新结构和寿命评估规则，这些部件需要以低频或稳定运行周期进行循环使用，或两者兼有。 4.2在每种情况下，建议具有互补的连续循环疲劳数据（以相同的应变/加载速率收集）和根据实践进行的试验确定的蠕变数据 E139 对于相同的材料和测试温度。该程序主要涉及在力或应变控制下（至少远程）承受单轴载荷的圆棒试样的测试。 该程序的重点是在给定循环内同时产生蠕变和疲劳变形及损伤的试验。根据在此类条件下进行的蠕变疲劳试验确定的数据可以表征 （a） 循环应力应变变形响应 （b） 循环蠕变（或松弛）变形响应 （c） 循环硬化、循环软化响应或（d）裂纹形成循环，或两者兼而有之。 4.3虽然有许多测试标准和实践规范涵盖了低周疲劳变形和裂纹萌生性能循环的确定（见实践） E606 ，BS 7270:2000 ，JIS Z 2279–1992 ，PrEN 38741998 ，PrEN 3988–1998 ，ISO 12106-2003 ，ISO 12111-2005 ，并练习 E2368 -04和 ( 1. , 2. , 3. ) 7. ，其中一些为高温测试提供了指导（例如，实践 E606 ，ISO 12106-2003 ，并练习 E2368 -04，没有一个标准专门规定蠕变疲劳试验程序。

1.1 This test method covers the determination of mechanical properties pertaining to creep-fatigue deformation or crack formation in nominally homogeneous materials, or both by the use of test specimens subjected to uniaxial forces under isothermal conditions. It concerns fatigue testing at strain rates or with cycles involving sufficiently long hold times to be responsible for the cyclic deformation response and cycles to crack formation to be affected by creep (and oxidation). It is intended as a test method for fatigue testing performed in support of such activities as materials research and development, mechanical design, process and quality control, product performance, and failure analysis. The cyclic conditions responsible for creep-fatigue deformation and cracking vary with material and with temperature for a given material. 1.2 The use of this test method is limited to specimens and does not cover testing of full-scale components, structures, or consumer products. 1.3 This test method is primarily aimed at providing the material properties required for assessment of defect-free engineering structures containing features that are subject to cyclic loading at temperatures that are sufficiently high to cause creep deformation. 1.4 This test method is applicable to the determination of deformation and crack formation or nucleation properties as a consequence of either constant-amplitude strain-controlled tests or constant-amplitude force-controlled tests. It is primarily concerned with the testing of round bar test specimens subjected to uniaxial loading in either force or strain control. The focus of the procedure is on tests in which creep and fatigue deformation and damage is generated simultaneously within a given cycle. It does not cover block cycle testing in which creep and fatigue damage is generated sequentially. Data that may be determined from creep-fatigue tests performed under conditions in which creep-fatigue deformation and damage is generated simultaneously include (a) cyclic stress- strain deformation response (b) cyclic creep (or relaxation) deformation response (c) cyclic hardening, cyclic softening response (d) cycles to formation of a single crack or multiple cracks in test specimens. Note 1 — A crack is believed to have formed when it has nucleated and propagated in a specimen that was initially uncracked to a specific size that is detectable by a stated technique. For the purpose of this standard, the formation of a crack is evidenced by a measurable increase in compliance of the specimen or by a size detectable by potential drop technique. Specific details of how to measure cycles to crack formation are described in 9.5.1 . 1.5 This test method is applicable to temperatures and strain rates for which the magnitudes of time-dependent inelastic strains (creep) are on the same order or larger than time-independent inelastic strain. Note 2 — The term inelastic is used herein to refer to all nonelastic strains. The term plastic is used herein to refer only to time independent (that is, non-creep) component of inelastic strain. A useful engineering estimate of time-independent strain can be obtained when the strain rate exceeds some value. For example, a strain rate of 1×10 -3 sec -1 is often used for this purpose. This value should increase with increasing test temperature. 1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.7 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 ====== 4.1 Creep-fatigue testing is typically performed at elevated temperatures and involves the sequential or simultaneous application of the loading conditions necessary to generate cyclic deformation/damage enhanced by creep deformation/damage or vice versa. Unless such tests are performed in vacuum or an inert environment, oxidation can also be responsible for important interaction effects relating to damage accumulation. The purpose of creep-fatigue tests can be to determine material property data for (a) assessment input data for the deformation and damage condition analysis of engineering structures operating at elevated temperatures (b) the verification of constitutive deformation and damage model effectiveness (c) material characterization, or (d) development and verification of rules for new construction and life assessment of high-temperature components subject to cyclic service with low frequencies or with periods of steady operation, or both. 4.2  In every case, it is advisable to have complementary continuous cycling fatigue data (gathered at the same strain/loading rate) and creep data determined from test conducted as per Practice E139 for the same material and test temperature(s). The procedure is primarily concerned with the testing of round bar test specimens subjected (at least remotely) to uniaxial loading in either force or strain control. The focus of the procedure is on tests in which creep and fatigue deformation and damage is generated simultaneously within a given cycle. Data which may be determined from creep-fatigue tests performed under such conditions may characterize (a) cyclic stress-strain deformation response (b) cyclic creep (or relaxation) deformation response (c) cyclic hardening, cyclic softening response or (d) cycles to crack formation, or both. 4.3 While there are a number of testing Standards and Codes of Practice that cover the determination of low cycle fatigue deformation and cycles to crack initiation properties (See Practice E606 , BS 7270: 2000 , JIS Z 2279–1992 , PrEN 3874, 1998 , PrEN 3988–1998 , ISO 12106–2003 , ISO 12111–2005 , and Practice E2368 -04 and ( 1 , 2 , 3 ) 7 , some of which provide guidance for testing at high temperature (for example, Practice E606 , ISO 12106–2003 , and Practice E2368 -04, there is no single standard which specifically prescribes a procedure for creep-fatigue testing.