Cyclic and static creep behavior of Al–Cu alloy composite reinforced with in-situ Al2O3 and TiB2 particulates

Abstract

Static and cyclic creep tests were carried out in tension at 573-623 K on Al-4wt.%Cu alloy (Al2O3.TiB2/Al-Cu) composite reinforced with in-situ 11.1 vol.%Al2O3 and 8.9 vol.%TiB2 particulates. The Al2O3.TiB2/Al-Cu composite exhibited an apparent stress exponent of 11.8-12.6 and 22.2-23.3 and an apparent activation energy of 337 and 421 kJ/mol for static and cyclic creep, respectively. The values of apparent stress exponent and activation energy for cyclic creep of the Al2O3.TiB2/Al-Cu composite were much higher than those obtained from the static creep measurements. Cyclic creep retardation (CCR) behavior was observed in the Al2O3.TiB2/Al-Cu composite. Furthermore, the steady state creep rate for cyclic creep tended to decrease with increasing the loading frequency and percentage of unloading amount. The CCR behavior is explained in terms of the storage of anelastic strain delaying nonrecoverable creep during the on-load cycles. Finally, the creep rupture behavior of the Al2O3.TiB2/Al-Cu composite is best described by Monkman-Grant and Dobes-Milicka empirical equations. (C) 1999 Elsevier Science S.A. All rights reserved.