Abstract
This paper reports the microstructure and creep behaviour of an Al–Cu–Mg–Ti–Ag alloy processed via Osprey forming and extrusion. The microstructure of the as-received extruded bars showed elongated grains towards the extrusion direction, which contained a fine substructure. Elongation to failure values of about 25% were obtained at test temperatures up to 400 °C and for strain rates ranging from 10−4 to 10−2 s−1. In this temperature range, the mechanical behaviour of the alloy was similar to that of particle-strengthened aluminium alloys: (1) the apparent stress exponents of n = 17 and 7 were higher than that reported for most aluminium alloys; (2) the microstructure and the texture did not change significantly during tensile deformation. At temperatures higher than 400 °C, the elongated grains of the microstructure started to recrystallize into smaller grains and a maximum elongation to failure of 170% was observed at 520 °C and 10−4 s−1. Tensile tests performed at higher strain rates in this temperature range revealed a stress exponent of 4.5, which corresponds to a slip creep mechanism
M. Eddahbi thanks the Grant 345/2000 from the Comunidad
Aut´onoma de Madrid. The authors gratefully acknowledge the
support of the Comisi´on Interministerial de Ciencia y Tecnolog´ıa
(CICYT) under Grant MAT2003-5108.
Peer reviewed