Ageing and work-hardening behaviour of a commercial AA7108 aluminium alloy

In the 7xxx aluminium alloying system several mechanisms influence the hardening behaviour of the alloys, e.g. particle size and distribution, dislocation density and alloying elements in solid solution. This work is an experimental study of ageing and work-hardening considering a commercial AA7108 alloy in the as-cast and homogenized condition. Tensile specimens have been exposed to a solution heat treatment and a two-step age-hardening treatment with varying time at the final temperature. The tensile data for the different tempers have been evaluated in elucidation of already existing models based on a one-parameter framework. The precipitate size and distribution have been further investigated in the transmission electron microscope for a selection of tempers, and the influence of these parameters on the work-hardening behaviour has been discussed. (C) 2009 Elsevier B.V. All rights reserved.