ASTM E831

Coefficients of linear thermal expansion are used, for example, for design purposes and to determine if failure by thermal stress may occur when a solid body composed of two different materials is subjected to temperature variations.

This test method is comparable to Test Method D 3386 for testing electrical insulation materials, but it covers a more general group of solid materials and it defines test conditions more specifically. This test method uses a smaller specimen and substantially different apparatus than Test Methods E 228 and D 696.

1. Scope

1.1 This test method determines the apparent coefficient of linear thermal expansion of solid materials using thermomechanical analysis techniques. Related information can be found in Refs. (, ).

1.2 This test method is applicable to solid materials that exhibit sufficient rigidity over the test temperature range such that the sensing probe does not produce indentation of the specimen.

1.3 The recommended lower limit of coefficient of linear thermal expansion measured with this test method is 5 m/(mC). The test method may be used at lower (or negative) expansion levels with decreased accuracy and precision (see Section ).

1.4 This test method is applicable to the temperature range from 120 to 900 C. The temperature range may be extended depending upon the instrumentation and calibration materials used.

1.5 Computer or electronic based instruments, techniques, or data treatment equivalent to this test method may also be used.

Users of this test method are expressly advised that all such instruments or techniques may not be equivalent. It is the responsibility of the user to determine the necessary equivalency prior to use.

1.6 SI values are the standard.

1.7 This test method is related to ISO 11359-2 but is significantly different in technical detail.

This standard does not purport to address all of the safety problems, 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.

2. Referenced Documents

D3386 Test Method for Coefficient of Linear Thermal Expansion of Electrical Insulating Materials
D696 Test Method for Coefficient of Linear Thermal Expansion of Plastics Between -30C with a Vitreous Silica Dilatometer
E1142 Terminology Relating to Thermophysical Properties
E1363 Test Method for Temperature Calibration of Thermomechanical Analyzers
E2113 Test Method for Length Change Calibration of Thermomechanical Analyzers
E228 Test Method for Linear Thermal Expansion of Solid Materials With a Push-Rod Dilatometer
E473 Terminology Relating to Thermal Analysis and Rheology
ISO 11359-2 Plastics-Thermomechanical Analysis (TMA)-Part 2: Determination of Coefficient of Linear Thermal Expansion and Glass Transition Temperature

Index Terms

linear expansion; solid materials; thermal expansion coefficient; thermomechanical analysis; ICS Number Code 19.060

Citing ASTM Standards

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