A European consortium is evaluating materials for the construction of a new supersonic transport aircraft that may replace Concorde. Current designs propose to use an aluminium alloy for the fuselage which is required to have superior creep resistance and damage tolerance to the Concorde alloy 2618A. Promising results have been obtained with extruded Al-Cu alloys containing minor additions of magnesium and silver which stimulate hardening by the relatively stable V precipitate. Data is presented which shows that these alloys have tensile and accelerated creep properties which are better than those of competing commercial alloys of the 2000 series, together with satisfactory levels of fracture toughness. Of the four experimental alloys studied, the optimal composition is Al-5·6Cu-0·45Mg-0·45Ag-0·30Mn-0·18Zr (wt-%).

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This paper presents the results of a cooperative study between AEROSPATIALE, DASSAULT AVIATION, BRITISH AEROSPACE, ALENIA, IMPERIAL COLLEGE, CEREM, ALPOCO, RAUFOSS A/S, CENIM AND THE UNIVERSITY OF PISA supported by the CEC under BRITE EURAM contract BREU 0356 C which aims at developping a new Aluminium alloy for use at 250 -300°C by Rapid Solidification /Powder Metallurgy technology. Tensile and creep properties at temperatures up to 350°C, fracture .toughness and corrosion results on 11 alloys from the A1-Fe-V, Al-Fe-Mo, Al-Cr-Ni and Al-Mn-Ni systems are presented and discussed. Their stability for long exposures at temperatures up to 350°C is demonstrated on the basis of fine microstructural investigations and mechanical tests.The cross effect of the Iron content and the powder size distribution is detailed in the case of the gas atomization process for the A1-Fe-V system. The results obtained on the most promising products are detailed and compared to those available on existing 8009 and 8019 alloys. Potential applications on aerospace structures are described.

Initiation and microcrack propagation stages were investigated by optical microscopic observations of fatigue damage . The differerices observed at high fatigue lives on S-N curves are found to correlate with the nature of initiation sites . It is shown that microcrack growth rates are equivalent for both 2024 T351 and 2091 T8 alloys, though long crack growth rates for 2091 T8 are lower as compared to those of 2024 T351 .

The 2091 alloy was tested to determine toughness levels with respect to heat treatment. A drastic decrease in fracture toughness was observed as a function