GRAIN SIZE OF ELECTROCORUNDUM SINTERED FROM DISPERSED WASTE ALUMINUM GRADE AD0E

Abstract

To develop technologies for obtaining electrocorundum by spark plasma sintering of aluminum waste dispersed by electroerosion and to evaluate the effectiveness of their practical application, comprehensive theoretical and experimental studies are required. The purpose of this work was the grain size of electrocorundum sintered from dispersed aluminum waste of the AD0E brand. Electrodispersion of aluminum waste of the AD0E brand was carried out in distilled water at the original installation with a capacity of 65.5 UF discharge capacitors, a voltage at the electrodes of 200 V, a pulse repetition frequency of 200 Hz. As a result of exposure to short-term electrical discharges, particles of electroerosive powder of various sizes were formed in the water. Further, the fusion of the electroerosion charge was carried out in the spark plasma fusion system SPS 25-10 "Thermal Technology" (USA) at a pressure of 30 MPa, a temperature of 560 °C and a holding time of 3 minutes. Analysis of the microstructure of sintered electrocorundum showed that it has a fine-grained structure, without inclusions, uniform phase distribution and the absence of significant pores, cracks and discontinuities. The grain size of the studied alloys, determined using the SIMAGIS Photolab automated image analysis system and the OLYMPUS GX51 optical inverted microscope, was about 0.45 microns. The small grain size of the resulting electrocorundum is associated with the high dispersion of the initial electroerosion charge and the effect of "grain growth suppression" during spark plasma fusion due to the short working cycle time, high pressure and uniform heat distribution over the sample when exposed to pulsed electric current and the so-called "spark discharge plasma effect". The conducted studies will allow to perform resource conservation and import substitution in the production of electrocorundum from aluminum waste of the AD0E brand.