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B. Bauer, G. Requena:
"Creep Resistance depending on Particle Reinforcement Size of Al-Alloys produced by Powder Metallurgy";
Talk: International Conference on Powder Metallurgy and Particulate Materials - POWDERMET2009, Las Vegas - USA; 06-28-2009 - 07-01-2009; in: "International Conference on Powder Metallurgy and Particualte materials", (2009), ISBN: 978-0-9819496-1-1; 1 - 13.

The Young´s Modulus, the high temperature strength and the tensile creep behaviour are investigated for unreinforced and particle reinforced AA2124 and AA6061 matrices with 25vol% of SiC particles with different sizes. The materials were produced via powder metallurgy and subsequent extrusion. The blending of the metallic powders and the SiC particles was carried out by wet blending (WB) and ball milling (BM). The SiC particles size in WB samples seems less affected by the blending operation, but the bigger particles are affected by the extrusion process. The BM process fractures the SiC particles leading to sub-µm SiC particles and a significant amount of oxide dispersoids is incorporated.
The Young´s Modulus is increased by about 50% compared to the unreinforced alloys due to the introduction of the stiffer SiC particles regardless of the initial particle size. All BM samples and only SiC particles <5µm in WB samples provide increased hot tensile strength. The stationary creep rate of composites produced by BM is two orders of magnitude lower than that of the WB composites and the unreinforced matrices. This enhancement of creep resistance of BM composites is achieved by the presence of dispersoids as a result of BM. The creep resistance of the WB composites decreases the larger the particle size acting as dislocation sources. A similar behaviour is observed for the high temperature strength for which the dispersoids in the BM composites increase the strength, while the larger SiC particles decrease the strength with respect to the matrices.