查看文章

Practical interest in beryllium arises mainly from its low mass density (lowest among rigid metals), low atomic number (transparent to x rays, high neutron reflector), and special alloying properties (springs, electrical contacts). We remeasured beryllium’s elastic constants for three principal reasons:(1) to use a modern resonance method (resonance-ultrasound spectroscopy) to acquire improved values, especially for the off-diagonal Cij; for example, previous reports give the Poisson ratio, a key design parameter, with an uncertainty of 63%;(2) for the hexagonalsymmetry case, to consider the monocrystal–polycrystal ‘‘averaging’’theories by measuring also polycrystal beryllium;(3) to use our improved Cij to calculate a Debye characteristic temperature, which relates in turn to various solidstate properties. Several theorists have called for new Cij measurements, claiming they are needed to choose among various …