Table of Contents
International Journal of Metals
Volume 2014, Article ID 748595, 7 pages
http://dx.doi.org/10.1155/2014/748595
Research Article

Modification of Magnesium Alloys by Ceramic Particles in Gravity Die Casting

1Institute of Materials Physics and Technology, Hamburg University of Technology, Eißendorfer Straße 42, 21073 Hamburg, Germany
2Helmholtz-Zentrum Geesthacht, Magnesium Innovation Centre (MagIC), Max-Planck-Straße 1, 21502 Geesthacht, Germany

Received 2 June 2014; Accepted 12 October 2014; Published 30 October 2014

Academic Editor: Manuel Vieira

Copyright © 2014 Urs Haßlinger et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

A critical drawback for the application of magnesium wrought alloys is the limited formability of semifinished products that arises from a strong texture formation during thermomechanical treatment. The ability of second phase particles embedded into the metal matrix to alter this texture evolution is of great interest. Therefore, the fabrication of particle modified magnesium alloys (particle content 0.5–1 wt.-%) by gravity die casting has been studied. Five different types of micron sized ceramic powders (AlN, MgB2, MgO, SiC, and ZrB2) have been investigated to identify applicable particles for the modification. Agglomeration of the particles is revealed to be the central problem for the fabrication process. The main factors that influence the agglomerate size are the particle size and the intensity of melt stirring. Concerning handling, chemical stability in the Mg-Al-Zn alloy system, settling and wetting in the melt, and formation of the microstructure in most cases, the investigated powders show satisfying properties. However, SiC is chemically unstable in aluminum containing alloys. The high density of ZrB2 causes large particles to settle subsequent to stirring resulting in an inhomogeneous distribution of the particles over the cast billet.