Thermal Expansion Coefficients of Common Materials
Reference table for linear thermal expansion coefficients (α) across metals, plastics, ceramics, and composites
Thermal Expansion Coefficients Comparison Table
| Material | α (×10⁻⁶ /°C) |
|---|---|
| Aluminum | 23 |
| Steel (Carbon) | 12 |
| Stainless Steel | 16 |
| Copper | 17 |
| Brass | 19 |
| Bronze | 18 |
| Nickel | 13 |
| Titanium | 9 |
| Cast Iron | 11 |
| Glass (Soda-Lime) | 9 |
| Borosilicate Glass | 3.3 |
| Quartz | 0.5 |
| Alumina (Ceramic) | 8 |
| Silicon Carbide | 4 |
| Polyethylene (PE) | 100 |
| Polypropylene (PP) | 100 |
| Polystyrene (PS) | 70 |
| Polycarbonate (PC) | 65 |
| Epoxy Resin | 50 |
| Concrete | 12 |
| Wood (Along Grain) | 3 |
| Wood (Across Grain) | 30 |
| Bricks | 5 |
| Aluminum Alloy 6061 | 23.6 |
| Magnesium | 26 |
| Zinc | 30 |
| Lead | 28 |
| Tungsten | 4.5 |
| Gold | 14 |
| Silver | 19 |
Thermal Expansion Coefficients Comparison Chart
About Linear Thermal Expansion Coefficient (α) of Materials
The linear thermal expansion coefficient (symbol: α) is a fundamental material property that describes how the length of a solid material changes with temperature. It is widely used in engineering design, construction, manufacturing, and materials science to predict dimensional changes and ensure structural stability under temperature variations.
Definition and Standard Formula
The change in length of a material can be calculated using the formula:
ΔL = α × L₀ × ΔT
Here, ΔL is the change in length, L₀ is the original length, and ΔT is the temperature difference. The coefficient α enables engineers to predict expansion or contraction for metals, plastics, ceramics, and composites.
Importance in Engineering and Materials Science
Understanding thermal expansion coefficients is essential to prevent structural stress, cracking, warping, or thermal fatigue in temperature-sensitive applications. It is particularly important for:
- Mechanical Engineering: Designing assemblies, machinery, and precision instruments where dimensional stability is critical.
- Construction & Civil Engineering: Accounting for expansion in concrete, steel, bricks, and other building materials.
- Aerospace & Automotive: Ensuring components tolerate thermal cycling and extreme operating temperatures.
- Electronics & Composites: Managing thermal stress in circuit boards, polymers, and layered materials.
- Materials Research: Selecting materials with compatible α values to minimize deformation in multi-material systems.
Accurate knowledge of linear thermal expansion coefficients ensures reliable engineering design, structural safety, manufacturing precision, and materials selection, making it a vital reference in both practical and research settings.