This article is cited in 7 papers

Mechanical properties, strength physics and plasticity

Mechanism of formation of cellular dislocation structures during propagation of intense shock waves in crystals

G. A. Malygin^a, S. L. Ogarkov^b, A. V. Andriyash<sup>b

a</sup> Ioffe Institute, St. Petersburg
^b All-Russia Research Institute of Automatics named after N L Dukhov, Moscow

Abstract: The mechanism of formation of a cellular dislocation structure in face-centered cubic (fcc) metal crystals subjected to shock compression at strain rates $\dot{\varepsilon}>$ 10$^6$ s$^{-1}$ has been considered theoretically within the dislocation kinetic approach based on the kinetic equation for the dislocation density (dislocation constitutive equation). A dislocation structure of the cellular type is formed in the case of a two-wave structure of the compression wave behind its shock front (elastic precursor). It has been found that, at pressures $\sigma>$ 10 GPa, the dislocation cell size $\Lambda_c$ depends on the pressure $\sigma$ and the density $\rho_G$ of geometrically necessary dislocations generated at the shock front according to the relationship $\Lambda_c\sim\rho_G^{-n}\sim\sigma^{-m}$, where $n$ = 1/4–1/2, $m$ = 3/4–3/2, and $m$ = 1, for different pressures and orientations of the crystal. It has been shown that, in copper and nickel crystals with the shock loading axis oriented along the [001] direction, the cellular structure is not formed after reaching the critical pressures $\sigma$ c equal to 31 and 45 GPa, respectively.

Received: 12.12.2013

 English version: Physics of the Solid State, 2014, 56:6, 1168–1176

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