Compositional Effects on the Restoration Behaviour in Mg-Zn-RE Alloys

Abstract:

Additions of rare earth elements to magnesium alloys are qualitatively reported in the literature to retard recrystallisation. However, their effect in the presence of other (non-rare earth) alloy additions has not been systematically shown nor has the effect been quantified. The microstructural restoration following the hot deformation of Mg-xZn-yRE (x = 2.5 and 5 wt.%, y = 0 and 1 wt.%, and RE = Gd and Y) alloys has been studied using double hit compression testing and microscopy. It was found that, in the absence of rare earth additions, increases in zinc level had a negligible influence on the kinetics of restoration and the microstructure developed both during extrusion and throughout double hit testing. Adding rare earth elements to Mg-Zn alloys was found to retard restoration of the microstructure and maintain finer recrystallised grains. However, in the Mg-Zn-RE alloys, increasing the zinc concentration from 2.5 wt.% to 5 wt.% accelerated the restoration process, most likely due to a depletion of rare earth elements from solid solution and modification of the particles present in the matrix.

• Periodical: Materials Science Forum (Volume 765)
• Pages: 18-22
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.765.18
• Online since: July 2013
• Authors: Nigel G. Ross, Matthew R. Barnett, Aiden G. Beer
• Keywords: Restoration Kinetics, Wrought Mg-Zn-RE Alloys

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