[edit]Characteristics

[edit]Physical properties

Beryllium has exceptional flexural rigidity (Young's modulus 287 GPa) and a reasonably high melting point.

The modulus of elasticity of beryllium is approximately 50% greater than that of steel.

The combination of this modulus and a relatively low density results in an unusually fast sound conduction speed in beryllium –

about 12.9 km/s at ambient conditions.

Other significant properties are high specific heat (1925 J·kg−1·K−1) and thermal conductivity (216 W·m−1·K−1),

which make beryllium the metal with the best heat dissipation characteristics per unit weight.

In combination with the relatively low coefficient of linear thermal expansion (11.4×10−6 K−1),

these characteristics result in a unique stability under conditions of thermal loading.[3]

[edit]Nuclear properties

Beryllium has a large scattering cross section for high-energy neutrons, about 6 barns for energies above ~0.01 eV.

Therefore, it effectively slows the neutrons to the thermal energy range of below 0.03 eV, where the total cross section is at least an order of magnitude lower – exact value strongly depends on the purity and size of the crystallites in the material. Surfaces". Journal of ASTM International 2 (9): 13168. doi:10.1520/JAI13168.

The predominant beryllium isotope 9Be also undergoes a (n,2n) neutron reaction to 8Be, which then instantaneously breaks into two alpha particles; that is, beryllium is a neutron multiplier, releasing more neutrons than it absorbs.

This nuclear reaction is:[4]