Paper number 212

PROPERTIES OF CAST MAGNESIUM MATRIX COMPOSITES AT ELEVATED TEMPERATURES

K.U. Kainer, F. Moll

Institut für Werkstoffkunde und Werkstofftechnik, Technische Universität Clausthal, Agricolastrasse 6, D-38678 Clausthal-Zellerfeld, Germany

Summary

The alloy AZ91 was used as matrix material for composites reinforced by 10 vol.% of SiC particles. The composites were produced by liquid mixing and squeeze casting. Apart from a few particle clusters the composites showed a uniform and homogenous particle distribution. Particles could be found both at grain boundaries and within the grains, indicating sufficient wetting of the particles by the molten metal. The unreinforced alloy was processed under the same conditions to enable a comparative evaluation of properties and microstructures. Tensile tests and creep tests under constant stress conditions up to 200°C were carried out. It could be observed, that the ultimate tensile strength of the as-cast MMC was increased by the particle reinforcement at 150°C and even at 200°C. A slight improvement of creep resistance due to the particle reinforcement became evident only when creep took place at the lower temperature and stress regime.

Keywords

magnesium matrix, stir-casting, SiC particles, particle reinforcement, properties at elevated temperatures, tensile strength, creep rate.