EDGE INSTABILITIES IN THIN PLATES STUDIED BY IN-SITU TRANSMISSION ELECTRON-MICROSCOPY

The morphological instability of thin foil edges at elevated temperatu re is studied by in situ TEM. Quasi-periodic instabilities in the edge profile are observed to develop with a distinct growth direction perp endicular to the original foil edge direction. This results in the dev elopment of relatively thick rods perpendicular to the original edge. The rods are then observed to undergo spheroidization. The use of in s itu techniques allows the direct study of the thickness changes associ ated with the formation and propagation of this instability. Such exam ination of the details of the thickness changes is critical to a full understanding and perhaps the control of the phenomenon.