IN-SITU HIGH-RESOLUTION ELECTRON SPECTROSCOPIC IMAGING OF PRECIPITATEGROWTH IN AN AL-AG ALLOY

High-resolution electron spectroscopic imaging of precipitate interfac es in an Al-Ag alloy was performed during in situ growth in a JEOL 201 0F transmission electron microscope equipped with a double-tilt heatin g holder and a Gatan imaging filter. These experiments demonstrate tha t it is possible to obtain sub-nanometer compositional information at interfaces during in situ heating studies. The results also show that the Ag gradient across moving ledges is more diffuse than across stati onary terraces, and that the compositional component of the transforma tion is fully achieved at the ledges, in agreement with the prediction s of transformation theory and the mechanisms of the phase transformat ion. (C) 1998 Elsevier Science Ltd. All rights reserved.