Title: Features of material structure formation during high-voltage powder consolidation
Abstract:
High-voltage powder consolidation forms a compact material structure through the combined action of external mechanical pressure and high-voltage pulsed current on a powder compact. The regularities of this process are largely governed by the localization of energy release at interparticle contacts during electropulse action on the powder blank. The compaction process is critically in§uenced by both the shape and size of the powder particles as well as the properties of the powder material, such as heat resistance and the temperature dependence of the yield strength. Theoretical analysis, computer modeling, and experimental studies of the high-voltage consolidation process have identi¦ed the conditions for various compaction regimes in cylindrical powder compacts. Wave compaction regimes along the axis of a cylindrical compact under mechanical pressure from punches have been established and investigated for materials whose yield strength decreases with increasing temperature. Additionally, radial compaction regimes for cylindrical compacts under magnetic pressure generated by a high-voltage current pulse have been determined. Radial compaction due to magnetic pressure dominates over axial compaction caused by the mechanical pressure of the punches in two distinct cases. First, when the magnetic pressure amplitude exceeds the mechanical pressure from the punches; and second, when the mechanical pressure is insu©cient to deform the spherical granules of the heat-resistant material during consolidation. A comprehensive microstructural analysis of the specimens consolidated under magnetic-pressure-driven radial compaction, alongside microstructural data of the specimens consolidated by wave compaction, reveals that the key distinction of magnetic-pressure-driven radial compaction is the extremely short-term, simultaneous pressure exposure across the entire volume of the material.
