|About this Abstract
||2021 TMS Annual Meeting & Exhibition
||Deformation Induced Microstructural Modification
||Ultrasonic consolidation of powders, foils, and wires: Mechanics and unifying physical mechanisms
||Zachary C. Cordero, Austin A Ward
|On-Site Speaker (Planned)
||Zachary C. Cordero
Ultrasonic consolidation techniques can rapidly form strong compacts from powder, foil, or wire feedstock with thermally unstable microstructures. In these techniques, a sonotrode applies a normal load to the charge while oscillating at ultrasonic frequencies perpendicular to the loading axis. The mechanical action of the sonotrode disrupts oxides and flattens asperities on the surfaces of the feedstock, enabling the growth of metallurgical junctions. Various theories have been proposed to explain the role of ultrasonic shearing in assisting densification, ranging from thermal softening via frictional heating to ultrasonic softening due to the interaction of glissile dislocations with elastic waves. This talk will summarize the mechanics of these ultrasonic consolidation processes and demonstrate that two key effects – frictional heating and normality of plastic strain – drive densification. The implications of this result for the processing of thermally unstable feedstock, such as metallic glasses and nanocrystalline alloys, will be discussed as well.