Magnesium Technology 2018: Keynote Session

Karl Kainer, MagIC—Magnesium Innovation Centre, Helmholtz-Zentrum Geesthacht, Germany
"Mg Alloys: Challenges and Achievements in Controlling Performance, and Future Application Perspectives"

In recent years, Mg alloys have made inroads into applications in transportation industries. Their favorable property profile promotes increased usage. Despite magnesium alloys being in service for years, there is still a lack of knowledge on potential of Mg alloys. New or optimized alloys and processes are creating new ideas to substitute traditional materials. While high-pressure die-casting is the dominant technology, other cast processes and wrought processing are only of secondary importance. Developments in the last decade have led to an improvement of the property profile and effectiveness of magnesium wrought alloys. Additive manufacturing opens new opportunities in tailoring of property profile and functionality. Mg as anode material for batteries opens a new field of application in the energy sector. This presentation will give an overview of the status of modern process and alloy development, and discuss the challenges in extension of use of magnesium alloys for various applications.

William Curtin, École Polytechnique Fédérale de Lausanne, Switzerland
"Solute/Stacking Fault Energies in Mg and Implications for Ductility"

Mg is the lightest structural metal but with low ductility due to the strong plastic anisotropy and fast pyramidal-basal (glissile-sessile) transitions of dislocations. Alloying generally improves Mg ductility. Especially, Mg-3wt.%RE (RE=Y, Tb, Dy, Ho, Er) show significantly enhanced ductility compared to Mg-Al-Zn commercial alloys. To investigate possible ductilization mechanisms and the special roles of RE solutes, first-principles calculations are used to compute all relevant stacking fault (SF) energies as a function of solute type (Y, Al, Zn) and concentration in the dilute limit. Results show that the effect of dilute Y solutes on any individual SF energy can be achieved by Al or Zn at similar or moderately higher concentrations, which does not support existing concepts related to I1 SF. Moreover, Y solutes have limited influence on the energetics of the undesirable pyramidal-basal transition. Other possible concepts for the mechanism(s) of enhanced ductility will then be discussed.

Nick Birbilis, Monash University, Australia
“Recent Developments in Magnesium Alloy Corrosion Research”

When exposed to atmospheric or aqueous conditions, magnesium undergoes corrosion, and so do magnesium alloys. In recent years, there has been a transition from accepting the corrosion of magnesium alloys, to proactive research aimed at (1) clarifying magnesium corrosion mechanisms to devise methods for restricting magnesium corrosion, and (2) demonstration of methodologies to produce more corrosion-resistant magnesium alloys. In this presentation, a number of examples will be shown, and they are selected on the basis that they represent a design-directed approach.

Mikhail Zheludkevich, MagIC—Magnesium Innovation Centre, Helmholtz-Zentrum Geesthacht, Germany
"Towards Active Corrosion Protection of Mg Alloys Using Corrosion Inhibition Approaches"

Corrosion susceptibility significantly limits the application range of magnesium alloys. Recently it was demonstrated that noble impurities present in Mg-based materials can play a detrimental role for corrosion resistance. One of the important mechanisms is related to the enhanced cathodic activity at the corrosion front and the superfluous hydrogen caused by iron re-deposition process. The effect drastically accelerates corrosion of impurity containing Mg. In the present work a new inhibition approach based on the complexation of Fe ions and consequently preventing re-deposition is suggested. The newly discovered corrosion inhibitors are integrated within protective coatings in order to obtain active corrosion protection effect for Mg alloys.