Characteristics of Mechanically Alloyed Al-Li Alloy, AL-905XL

Characteristics of mechanically alloyed carbide and oxide dispersion strengthened Al-Li alloy, IncoMAP ® alloy AL-905XL extrusion and its forging were investigated to examine whether it could be applied to structural materials in aircraft, aerospace and other industries, and following results were obtained. (1) No age hardening occurred although AL-905XL contains 1.3mass% Li which is precipitation hardening element. (2) Hardness and microstructure did not chang after long exposure at 573K. (3) By forging the extruded bar, though 0.2% proof stress decreased, ductility, fracture toughness and crack growth resistance were improved. As for unisotropy of these characteristics of the forging, longitudinal direction was much better than both long and short transverse ones which showed comparable values. In comparison with conventional aluminum alloys, proof stress and ductility were equal to or better than 7075-T7351, and fracture toughnes was between 7075-T651 and 7074-T7351. The crack growth rate was comparable to 7075-T7351 at higher ΔK, however was slightly larger than it at lower ΔK. (4) Fatigue property of AL-905XL extrusion was superior to 7075-T6. (5) Stress corrosion cracking resistance of AL-905XL forging was comparable to 7075-T7351. Exfoliation corrosion resistance was much better than 7075-T651.