Structure Evolution in Annealed and Hot Deformed AlMg-CeO2 Composite

A brief review of structural investigation and results of mechanical tests for mechanically alloyed AlMg-based composite reinforced with 9 wt.% addition of CeO2 is presented. The as extruded and annealed samples were examined by means of SEM, TEM and X-ray analysis. Heavily refined matrix grains and particles of cerium oxides were observed in the as extruded material. Fine microstructure attained by mechanical alloying and high affinity of oxygen to aluminum-magnesium matrix results in promoted solid state reactions between the matrix and reinforcements at elevated temperatures. Consequently, Al4Ce intermetallic grains and Al/Mg oxides are formed in the result of CeO2 decomposition. Hot compression tests were performed at constant true strain rate of 5·10-3 s-1 within the temperature range of 293 – 823K. Highly refined structure of the material was found to result in high strength of the composite, particularly for samples tested at low and intermediate temperatures.