Beryllium

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Beryllium is a hard, brittle, gray-white metal with physical and mechanical properties, including high heat capacity and thermal conductivity, that make it especially suitable for electronic components and specialized aerospace applications. Beryllium is particularly well suited for use as a structural material in space technology as it is the lightest structural metal known. Because of its combination of low weight, high stiffness and certain mechanical properties, such as a precise elastic limit, and transparency to x-rays and other high-energy electromagnetic radiation, beryllium is an excellent material for use in optical components and precision instruments. Beryllium is also used as an alloying element in copper, nickel, aluminum and magnesium alloys. 

Typical Properties:

  • Crystal Structure:
    • α phase, close-packed hexagonal; a = 0.22858 nm, c = 0.35842 nm at room temperature
    • β phase, body-centered cubic; a = 0.255 nm at 1270 oC
  • Atomic Weight: 9.0122
  • Density: 1.848 g/cm3 at 20 oC
  • Melting Point: 1283 oC
  • Boiling Point: 2770 oC
  • Coefficient of Linear Thermal Expansion: 18.4 µm/m ⋅ K (average coefficient), 25 oC - 1000 oC
  • Specific Heat: 1.886 kJ/kg ⋅ K at 20 oC
  • Latent Heat of Fusion: 1.30 MJ/kg
  • Thermal Conductivity: 210 W/m ⋅ K
  • Electrical Conductivity: 38 to 43% IACS
  • Electrical Resistivity: 40 nΩ ⋅ m at 20 oC
  • Temperature Coefficient of Electrical Resistivity: 0.025 Δρ/ρ()/K
  • Magnetic Susceptibility:  Mass: 
    • -0.79 x 10-9 mks at 93 K
    • -1.0 x 10-9 mks at 293 K
    • -1.2 x 10-9 mks at 573 K
  • Spectral Hemispherical Emittance: 61% for λ = 650 nm
  • Thermal Neutron Cross Section: 0.01 b
  • Hardness: 75 to 85 HRB
  • Poisson’s Ratio: 0.07 to 0.075 (vacuum hot pressed)
  • Elastic Modulus: 303 GPa
  • Impact Strength: 1.4 to 5.4 J
  • Plane-Strain Fracture Toughness: 9 to 13 MPa√m
  • Resistance to Specific Corroding Agents: Beryllium reacts appreciably with oxygen and nitrogen above 760 oC. Impure beryllium containing carbide or chloride reacts with moist air at room temperature. Beryllium does not react with hydrogen at any temperature; it reacts with fluorine at room temperature and with Cl, B, I, HCl, HF, and CO2 at elevated temperatures. Beryllium has excellent resistance to pure water at temperatures up to 300 oC if carbide and chloride are absent and if grain size is fine. Beryllium is attacked by dilute HF, HCl, H2SO4, and HNO3, at room temperature.