High-Speed Interaction of a Metal Jet with Ceramics
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peed Interaction of a Metal Jet with Ceramics B. V. Rumyantseva* and S. I. Pavlova a
Ioffe Physical Technical Institute, Russian Academy of Sciences, St. Petersburg, 194021 Russia *e-mail: [email protected] Received April 30, 2020; revised April 30, 2020; accepted May 25, 2020
Abstract—The destabilization of a cumulative jet with an initial velocity of more than 8 km/s upon penetration into brittle materials is studied. Using electron microscopy, the state of materials that remain in the cavity is analyzed. The observed phase transformations of copper and brittle materials in the residual cavity indicate high temperatures in the penetration region and reveal the effect of the thermodynamic parameters of the interacting materials on the destabilization of high-speed penetration. Keywords: high-speed impact, metal jet, brittle materials, melting, evaporation, protection. DOI: 10.1134/S1063785020090102
The study of the introduction of metal jets into condensed matter is of great practical importance in solving problems of protection against a high-speed impact with a speed of 2–10 km/s [1–4]. In the laboratory, a high-speed metal jet (HSMJ) is obtained by detonating explosive charges containing a conical funnel. In this study, the peculiarities of the interaction of a metal jet with an initial velocity of more than 8 km/s with brittle materials (silicon carbide and ultraporcelain) are investigated. In contrast to metals (duralumin AMG6) (Fig. 1), the penetration of HSMJs into brittle materials (BMs) is complicated by the radial action of split debris from the cavity surface in the barrier [2, 4– 10]. The scheme of the experiment for studying the penetration of a cumulative jet [6] is shown in Fig. 1, in which the following notations are introduced: 1 for a device for forming a jet with a copper funnel with a diameter of d = 20 mm and an angle of 30°, 2 for an obstacle made of AMG6 duralumin plates with a size of 10 × 60 × 60 mm (density 2.64 g/cm3) or silicon carbide plates with a size of 20 × 80 × 80 mm (density 3.0 g/cm3), and 3 for contact sensors for measuring time t of penetration of the jet to a depth of L. The experiment was carried out in a vacuum chamber at a pressure of less than 20 kPa. The experimental results of penetration into duralumin (circles) and silicon carbide (crosses) are shown in the calculated L–t diagram, in which the dashed curve is the result of calculation of penetration into the barrier in the onedimensional hydrodynamic approximation [3, 6], the solid curve is the trajectory of the collapse of the cumulative funnel, and the grid of oblique lines is the trajectory of motion of jet elements with a velocity of Vj. The experimental kinetics of penetration of an HSMJ into a BM is characterized by interruption and resumption of the penetration with an increase in the
time and a decrease in the incorporation depth (Fig. 1). Overcoming the region of collapse gives rise to interruption in the penetration trajectory and destabilization of the succeeding jet elements. As a result of systematic s
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