2021 Sorby Award Winner: Microscopy, Dislocations and Interfaces

This talk will combine three topics that have occupied the speaker for the past 50 years. TEM is the essential tool for fully characterizing, and thereby understanding, dislocations and interfaces in all materials, not only crystalline materials, but it is essential to combine TEM with other imaging techniques and with spectroscopy, particularly using X-rays generated and energy lost as the electrons interact with the specimen, to obtain a full picture. It is interesting to examine how early approaches to Materials Science have helped or hindered our understanding of imperfections in ceramics, metals and semiconductors. The talk will be illustrated by images of unusual defects in different materials and plans to conclude with suggestions of topics that should be revisited now that the tools and techniques for doing so can actually answer some of our earliest questions, keeping in mind why those were our earliest questions.