Why high pulsed currents shatter metal wires?

Summary form only given. There is compelling experimental evidence that a sufficiently high pulsed current would shatter a metal wire in the solid state. As a result the wire disintegrates in the solid state into many pieces. The experiments have shown that the wires break in tension owing to a certain longitudinal force. The search for the nature of this force lead in the past to some controversy. To determine the nature of the longitudinal tension induced in wires by high currents, and thus to establish the mechanism of the wire fragmentation, an extensive theoretical investigation has been performed. When a current passes through a metal wire two obvious effects occur. First, the wire material expands owing to Joule heating. Secondly, the wire is pinched radially by the Lorentz force. Both of these effects can induce stress waves in wires and lead to high tensile stress. Therefore, we have developed a magneto-thermo-elastic, numerical model of the phenomenon. As a result of the study several mechanisms of the wire fragmentation have been identified. These are: 1) The pinch effect and thermal expansion as a source of strong longitudinal vibrations. 2) The buckling instability due to simultaneous action of the thermal expansion and the magnetic force. 3) The flexural vibrations induced in initially bent wires. 4) The arc discharge created between broken wire ends leading to the appearance of strong longitudinal vibrations. These longitudinal vibrations result in further wire fragmentation into smaller pieces. It has been found that the induced elastic vibrations lead to the breaking of the wire in a wide range of parameters such as the total current and the wire geometry. The role of the skin effect in excitation of the oscillations has been identified.