Menu (ESC)

Thermal Expansion

Amount of change in a linear dimension per unit temperature change. Uses units of strain (unitless ratio of length change to original length) per unit temperature (temperature change). Positive temperature change is assumed (i.e. heating up).

Also called the coefficient of linear thermal expansion. A related, but seldom used, property is the volumetric thermal expansion, which, for isotropic materials, is equal to three times the linear.

Dimensionally-sensitive mechanisms need to account for dimensional changes brought on by changes in temperature. This is particularly vital if two parts with significantly different thermal expansion values are mated rigidly.

ASTM testing standards include D696, E228, and E831. ISO standards include 4897, 11359-2, and 17744.

Material Properties Explained

Material Properties Explained is a handbook published by It is a concise encyclopedia of engineering material properties. It is not tied to the material properties database, and covers a far larger number of properties than those used on the website. Subject matter includes:

  • Differences in definition and testing between types of materials.
  • Common testing variations and their significance.
  • What additional information is required to correctly interpret a value.
  • Any equations to calculate or estimate property values.
  • Synonyms and related terms.
  • Relevant international testing standards, including both ASTM and ISO.

To purchase a digital (PDF) copy: Material Properties Explained.

An unconditional 30 day money-back guarantee is provided. If the book disappoints you, email us, and we'll refund your money. No questions asked.