• Jackson, M.
• Henein, H.
• Dashwood, Richard
• Katsas, S.
• Todd, G.
• Grimes, R.

Abstract

When commercial superplastic aluminium alloys were first under development it was concluded that to be successful the alloy should contain both a solid solution addition and a dispersion of fine, thermally stable dispersoids. In contrast to early beliefs, the present work demonstrates that a simple Al–1 wt.%Zr alloy can exhibit good superplastic performance despite the absence of a solid solution element. The starting material was in the form of ∼1 mm diameter particles produce via impulse atomisation that conferred a solidification rate ∼103 K s−1. After extrusion consolidation, heat treatment to produce a fine distribution of metastable Al3Zr precipitates, and rolling, the resulting sheet exhibited superplastic ductilities in excess of 500% at a strain rate of 10−1 s−1. An EBSD study of the deformation behaviour demonstrated substantial grain refinement resulting from dynamic recrystallisation.

Topics

• dispersion
• grain
• extrusion
• aluminium
• zirconium
• precipitate
• electron backscatter diffraction
• solidification
• pure aluminum