Heat Transfer & Thermal

Coefficient of Thermal Expansion (CTE)

Definition

A material property indicating how much a material expands per unit length per degree of temperature change, denoted α. Units are 10⁻⁶/°C (ppm/°C). Linear expansion is calculated as ΔL = α × L₀ × ΔT.

Practical Note

Steel: α ≈ 12×10⁻⁶/°C. Aluminum: α ≈ 23×10⁻⁶/°C. Invar: α ≈ 1.2×10⁻⁶/°C. Plastics have much higher CTE (50-150×10⁻⁶/°C). Consider CTE mismatch when joining dissimilar materials.

Related Calculators

Related Terms