Beryllium (Be)
An exceptionally light and very stiff metal
Typical values for the temper in the title
Beryllium has a rare combination: a density of about 1.85 g/cm³ (lighter than aluminum), and an elastic modulus of about 300 GPa (stiffer than steel). Its stiffness-to-weight ratio is about 6 times that of steel and aluminum, and it stays dimensionally stable at extreme temperatures.
So it is used in space mirrors and optical structures, satellite and guidance components, and X-ray windows (it is transparent to them). The drawbacks: it is very expensive, has low ductility, and above all its dust is highly toxic.
Safety: beryllium dust, fumes and fine particles can cause serious chronic lung disease (CBD). Beryllium is machined only in licensed facilities with exhaust, containment and respiratory protection, under safety regulations.
Mechanical and physical properties
| Property | Value | Note |
|---|---|---|
| Tensile strength Rm | 370–450 MPa | |
| Yield strength Rp0.2 | 240–330 MPa | |
| Elongation A | 2–3% | |
| Hardness | 80–110 HB | |
| Modulus of elasticity E | 303 GPa | |
| Density ρ | 1.85 g/cm³ | |
| Machinability | 20% — toxic! dangerous dust | relative rating in the site database |
Chemical composition (wt %)
| Element | Range | Role |
|---|---|---|
| Be beryllium | about 98–99 (by grade) | |
| BeO beryllium oxide | about 1–2 (by grade) | strengthening |
Typical values. Grades are defined in producer specifications.
Conditions and product forms
Beryllium is made mainly by powder metallurgy (hot isostatic pressing). Properties depend on the grade.
| Condition | Properties | When to choose it |
|---|---|---|
| Hot isostatically pressed (HIP) | isotropic properties | mirrors and structures |
Applications
- Space mirrors and optical structures
- Satellite components
- Guidance systems
- X-ray windows
- Scientific instrument components
Fabrication
Safety
Only in licensed facilities. Never machine, grind or polish beryllium in an ordinary shop.
Processing
Possible in a suitable facility. The material is relatively brittle, and edge cracking must be avoided.
Joining
Welding is not recommended. Brazing and mechanical joining are common.
Compared with similar materials
| Material | Rm / Rp0.2 | Welding | When it is the better choice |
|---|---|---|---|
| AZ31B | 255–280 / 200 MPa | Good with Ar gas | magnesium: light, much less stiff · material page |
| 6061-T6 | 310 / 276 MPa | Good — ER4043 | aluminum: cheap, much less stiff · material page |
| C17200 (CuBe2) | 1380 / 1190 MPa | Electron beam / laser | beryllium copper: a copper alloy, not pure beryllium · material page |
Common mistakes
Machining beryllium in an ordinary shop
The dust is highly toxic. Only in a licensed facility.
Confusing it with beryllium copper
C17200 contains only about 2% beryllium. Pure beryllium is a completely different material.
Using it in an impact-loaded part
Ductility is low.
Equivalents, standards and supply
| Standards | Producer specifications (for example Materion) |
|---|---|
| Forms | plate · consolidated powder (HIP) |
| Producers | Materion · IBC Advanced Alloys |
Learn more
Values are typical and for comparison only. For design, rely on the standard, the producer specification and the mill certificate. Sources: ASTM standards (B86, B386, B392/B393, B551, B708, B760 and others), producer data, and the METAL HUB materials database.
Updated: October 31, 2026