New Al–Mg–Li–C dispersion strengthened alloy Part 1 – Composition and process development

Abstract

New fine grained aluminium–magnesium–lithium–carbon alloys, produced by mechanical alloying/powder metallurgy techniques, have been developed. The alloys are suitable for use in the as forged (T1) condition. A preferred chemistry (Al–5.2Mg–1.3Li–0.35%C, wt-%) has been defined, and methods for production of bulk (50 kg) billets and open die uniaxial forgings have been examined. These have produced attractive mechanical properties (0.2%PS=441 MPa, UTS=501 MPa and K_1C=23 MPa m^1/2) without recourse to cold compression. The new alloy is differentiated from AA 5091 by its much lower C content, and by being enriched in magnesium, which provides improved fracture toughness and superior powder handling ability. The balance of properties, achievable in a lightweight, non-heat-treatable alloy, make the alloy a candidate for aerospace, and other applications.