After Concorde: evaluation of creep resistant Al–Cu–Mg–Ag alloys

Abstract

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-%).

Effect of pre-straining on the aging behavior and mechanical properties of an Al–Cu–Mg–Ag alloy

“…The angle between the normal of the boundary plane and the normal of the Ω-phase platelets ranges from 0 to 451 to fit the orientation of this phase to a {111} α habit plane. Only one broad interface of a thick Ω-phase retains fully coherent configuration and specific OR [1,[3][4][5]8,12,14], while the opposite broad interface has a fully or partially semi-coherent structure, and OR at this interface deviate from the (001) Ω //(111) α on the value of misorientation (Z41) of a deformation-induced boundary (Fig. 16).…”

“…Age-hardenable aluminum alloys belonging to the Al-Cu-MgAg system are used in the aerospace industry due to their attractive combination of high specific strength, good fracture toughness and enhanced creep resistance attributed to the highly efficient strengthening by the Ω-phase [1][2][3][4][5][6][7][8][9][10]. This phase is a coherent modification of the equilibrium θ-phase (Al 2 Cu) that forms as a uniform dispersion of thin, hexagonal plates with large aspect ratios (diameter/thickness) on the {111} α habit planes [2][3][4][5][11][12][13][14][15].…”

Advances in positron studies of age hardening in light alloys

“…Microalloying with Ag as a quaternary element gives a better hardening response to Al-Cu-Mg, which is attributed to the presence of the orthorhombic phase Ω together with the tetragonal phase that forms in aged Al-Cu alloys [35,36]. Positron annihilation measurements by Nagai et al [31] demonstrated that Ag acts as a vacancy scavenger and helps to increase the number of vacancies retained after quenching.…”

The effect of nickel on shaping the structure of Al-Cu-Mn alloys

“…These alloys are extensively in use for high-quality castings in industrial applications, such as automotive and airplane parts [1,2]. The mechanical properties of Al-Cu alloys can be improved using various metallurgical parameters, including melt treatments, heat treatments, and alloying element additions [3].…”