The effect of atmosphere on the creep deformation of a particle reinforced aluminum alloy matrix composites

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 387; pp. 643 - 646
• Main Authors: Matsuda, Norio, Kikuchi, Koichi, Ishikawa, Satoshi, Saitoh, Mitsuru
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.12.2004
• Subjects: Alumina particles; Aluminum alloy matrix composite; Creep deformation; High temperature strength; High temperature strength; Aluminum alloy matrix composite; Creep deformation; Alumina particles
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2004.02.094

Creep behavior of the 6061 aluminum alloy matrix composite reinforced by 10 vol.% of alumina particles has been investigated at temperatures from 573 to 773 K in air and Ar atmospheres. Creep curves, stress dependence of the minimum creep rate, microstructures after creep deformation and the effect of the atmospheres on the creep behavior were examined. Deformation around grain boundaries was estimated by measuring the offset of marking lines across grain boundaries. Creep curves were dominated generally by tertiary creep in air and Ar at every temperature except in extremely low stress range at 773 K, where primary creep dominated. Large primary creep strain following an initial inverse type of transient creep was observed in air in the low stress range at 773 K. The effect of atmosphere was prominent only in the primary creep stage under extremely low stresses at high temperature. In the stage, large decrease in density and large deformation around grain boundaries with creep deformation in air were observed. Many voids and cracks were observed on the surface of the specimen crept in low stress range at 773 K in air. Filament like structures, which were seen to generate at particle-matrix interfaces or grain boundaries, were often observed on the fracture surfaces under the condition. Extremely high density of magnesium and oxygen was detected at the filament like structure by energy-dispersive X-ray spectrometry. The effects of the oxidation and the formation of the filament like structure on the creep behavior are discussed.