High-temperature creep behaviour of powder-metallurgy aluminium composites reinforced with SiC particles of various sizes

Tensile creep tests have been performed at 573-673 K on pure aluminium and aluminium-based composites reinforced with SiC par-tides of different sizes (3.5, 10 and 20 mu m) fabricated by powder-metallurgy (PM) techniques. Both the pure aluminium and the composites exhibited high values of the apparent stress exponent (14.3-26.1) and creep activation energy (253-261 kJ/mol). The results showed that the creep rate of composites reinforced with small particles (3.5 mu m) was two-three orders of magnitude lower than that of pure aluminium. However, the creep resistance of composites reinforced with large SiC particles (10 and 20 mu m) was essentially identical to that of pure aluminium. Various creep models were attempted to rationalize the creep data of pure aluminium and particulate composites. (C) 1999 Elsevier Science Ltd. All rights reserved.