This presentation covers the classification and comparison of different magnesium alloy systems in terms of their achievements towards healing each anomaly/problematic features that magnesium and its traditional alloys display. The shift in alloy design paradigm from Hume-Rotary rules and/or almost “trial and error” approach in selecting the alloying elements based on one final property expectation to more recent stacking fault energy (SFE) based alloying approach will be addressed. Thus the spectrum of alloy systems will range from doping (trace element additions) of magnesium, continue with dilute alloy systems, and go on to rich alloy systems, which involve solute-solution-proper systems and precipitate forming alloys. Among the first category, unorthodox addition like doping with oxygen or nitrogen with its implications will be presented. The dilute alloy systems and their SFE based design criteria together with their potentials will be examined. Finally, rich alloy systems with their wide spectrum will be categorized, and the interesting precipitate systems such as the ones involving quasi-crystals, long period stacking order (LPSO) phases, and more mundane intra- or inter granular precipitates will be discussed. In this last category, the trends in developing magnesium alloys that involve rare earth (RE) elements and RE-free ones will be presented in a comparative manner. Discussions on each category of alloy systems will further incorporate, whenever possible, the suitability of the alloy systems to particular processing routes. The article will also make an attempt to point out the future directions in closing comments.

Prof. Ali Arslan KAYA has been working as a full professor and Head of Department of Metallurgy and Materials Engineering Department, Engineering Faculty, Mugla Sitki Kocman University. He graduated as Metallurgical Engineer from Istanbul Technical University in 1984, and earned his MSc from the same university in 1986. He received his PhD from Oxford University, England in 1993. His fields of expertise are mainly materials characterization via electron microscopy, microanalysis, XRD and mechanical spectroscopy, and his areas of interests are steels, magnesium alloys and their processing. He has been lecturing on many different topics including physical metallurgy, alloys, solidification and casting, materials characterization, welding and history of metallurgy for over twenty years. Prof. Kaya is the author of two book chapters, 35 papers in international journals, and over seventy conference papers, and a co-editor of an international book on magnesium alloys. His publications have received 1370 citations with an h-index-19 so far. He is also the recipient of several national and international awards. He has also completed 8 national and 7 international projects as project manager.