Microstructure and Properties of Cast Metal Treated with Electromagnetic Pulses while in Molten State
The results of experiments on the impact of high power electromagnetic pulses (EMP) on the metal alloy melts are discussed. A generator with the following pulse parameters: the amplitude of 10 kV, the duration of 1 ns, the leading edge of 0.1 ns, repetition rate of 1 kHz was used for pulse electric treatment of metal melts. The maximum network input of the generator equals 100 watts. The treatment was carried out in a furnace immediately before casting. The treatment of the melt by electromagnetic pulses is conducted for 10-15 minutes. Comparative analysis of treated and untreated samples showed a change in structure, density, strength, ductility, and toughness of the cast metal. The mechanism of stepping impact on the metal melts was discussed. Analysis of the results of other external physical melt impact methods showed that the overall match is observed with the results of the ultrasonic treatment of metals. Therefore, the hypothesis of the pulse ultrasonic shock wave generation at the front was accepted as the basis-hypothesis for the mechanism of the impact of electromagnetic pulses on the melt. In the theoretical part of the paper a model of electromagnetic pulses conversion in acoustic pulses is proposed.