High kinetic energy penetrators

A second surface effect is due to the high kinetic energy and small mass of the free electrons (see Section 4.3). Electrons impinging on the surface wall may penetrate this wall this decreases their kinetic energy and increases their potential energy. Electrons spill over the surface plane, which corresponds to the center of the core ions. A time-averaged sketch of the distribution of the electrons and ions near the surface of a metal is presented in Figure 13(a). 

Research in tungsten heavy alloys was previously boosted by the ballistic application as anti-amor kinetic energy penetrator. Numerous papers have appeared in the last years and reviews have recently been published [6.29,6.39,6.40]. Although the basic requirements are the same for civil as for defense applications (i.e., high density, sn ngth, and elongation), there are two more important factors which must be considered for this specific application the behavior of the material imder high strain rate conditions and their ballistic performance (i.e., their penetration ability). In particular, the latter aspect is of critical importance and, to a certain extent, still a weak point of heavy metals. Their ballistic performance is inferior compared to depleted uranium, which is still used as a... 

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