1.1 本试验方法描述了通过三点弯曲中的挠度来实现试样比模量的温度测定。该温度被确定为畸变温度。变形温度是指具有规定几何形状的试样在施加应力0.455 MPa（66 psi）（方法a）和1.82 MPa（264 psi）（方法B）下变形至应变水平的温度，相当于试验方法中使用的温度 D648 . 该试验适用于环境温度至300°C的温度范围。 注1: 本试验方法旨在提供与试验方法类似的结果 D648 但使用较小的试样在热机械分析仪上进行。结果与通过试验方法获得的结果等效 D648 已经在有限数量的材料上进行了演示。本试验方法的结果应被视为独立于试验方法的结果，且与试验方法的结果无关 D648 除非用户证明等效。 1.2 没有与此测试方法等效的ISO标准。 1.3 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。 1.4 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。 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====== 5.1 通过本试验方法获得的数据不得用于预测材料在高温下的行为，除非在时间、温度、加载方法和应力条件与试验中规定的条件类似的应用中。 5.2 本标准特别适用于质量控制和开发工作。这些数据不用于设计或预测高温下的耐久性。

1.1 This test method describes the determination of the temperature at which the specific modulus of a test specimen is realized by deflection in three-point bending. This temperature is identified as the distortion temperature. The distortion temperature is that temperature at which a test specimen of defined geometry deforms to a level of strain under applied stress of 0.455 MPa (66 psi) (Method A) and 1.82 MPa (264 psi) (Method B) equivalent to those used in Test Method D648 . The test is applicable over the range of temperature from ambient to 300 °C. Note 1: This test method is intended to provide results similar to those of Test Method D648 but are performed on a thermomechanical analyzer using a smaller test specimen. Equivalence of results to those obtained by Test Method D648 has been demonstrated on a limited number of materials. The results of this test method shall be considered to be independent and unrelated to those of Test Method D648 unless the user demonstrates equivalence. 1.2 There is no ISO standard equivalent to this test method. 1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 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. 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 ====== 5.1 Data obtained by this test method shall not be used to predict the behavior of materials at elevated temperatures except in applications in which the conditions of time, temperature, method of loading, and stress are similar to those specified in the test. 5.2 This standard is particularly suited for quality control and development work. The data are not intended for use in design or predicting endurance at elevated temperatures.