Direct observation of the processes near particle-to-particle contacts at electric pulse consolidation of titanium powder

Abstract

Direct high-speed micro-video records prove the existence of highly overheated zones at the contacts of powder particles during short (~ 1 ms) electric current pulses. The value of overheating can exceed 1600 degrees and lead to the formation of liquid-phase sintering necks, the dimensions of which are well correlated with the size of the overheated zones. The micro-uniformity of the temperature field in the electric pulse heating allow understanding the unusually high consolidation rates of powder materials observed in spark plasma sintering.