MSE Seminar: Characterization of Solute Segregation and Precipitates in Light Alloys Using Advanced Scanning Transmission Electron Microscopy Techniques

Calit2 Auditorium
Jian-Feng Nie
Professor
Department of Materials Science and Engineering
Monash University
Melbourne, Victoria 3800, Australia

Abstract: Precipitation hardenable aluminium and magnesium alloys are two important groups of engineering light alloys. Mechanical properties of these alloys depend critically on their microstructures, which are strongly influenced by alloying elements and heat treatment processes. In conventional transmission electron microscopy, whilst information on the identity, spatial distribution and chemistry of precipitates could be readily obtained, it was difficult to reveal, at the atomic scale, the distribution of solute atoms or atoms of micro-alloying elements. It was for this reason that the roles of micro-alloying elements in precipitation of key strengthening intermetallic phases remained unresolved. Advances in scanning transmission electron microscopy (STEM) in the past 15 years, especially the aberration-corrected STEM techniques including high-angle annular dark-field (HAADF) and energy-dispersive X-ray spectroscopy (EDS), provide opportunities for detecting segregated solute atoms at the atomic scale. The purpose of this talk is to provide a review of the progress made in the understanding of precipitation and the role of micro-alloying elements in precipitation in selected aluminium and magnesium alloys, highlighting the importance of modern imaging and spectroscopy techniques of STEM in the characterization and development of these light alloys.

Bio: Jian-Feng Nie received his bachelor's degree in engineering from Beijing Institute of Technology in 1986 and his doctorate from Monash University in 1993. He is a professor at Monash University. His current research interests cover physical metallurgy of light alloys, applications of scanning transmission electron microscopy in materials characterization, and processing-microstructure-property relationships in light alloys. He has published one book, one book chapter and over 150 papers based on results obtained from imaging and diffraction techniques of electron microscopy. He has also edited proceedings of several major international conferences. He was awarded the Marcus Grossmann Young Authors Award of ASM International in 2006, AIME Champion Mathewson Medal Award of TMS in 2015, and TMS Extraction and Processing Division Technology Award in 2017. He is chair of the National Events Committee of Materials Australia.