GB709527A - Improvements relating to aluminium-base copper-containing alloys and the heat treatment thereof - Google Patents

Abstract

An aluminium alloy contains Cu 4.0-7.5 per cent., Cd 0.075-0.23 per cent., Mg less than 0.15 per cent., Sn less than 0.005 per cent., Mn not exceeding 1.5 per cent., Fe not exceeding 1.0 per cent., Si not exceeding 13.0 per cent., up to 2 per cent. in all of Zn (up to 1 per cent.), Ni (up to 1.5 per cent.), Cr. (up to 1 per cent.), Mo (up to 1 per cent.), Zr (up to 0.25 per cent.), Be (up to 0.25 per cent.), Ce (up to 0.25 per cent.), B (up to 1 per cent.), Ti (up to 0.5 per cent.), Ag (up to 1 per cent.), and Pb (up to 0.25 per cent.), and balance Al. The alloys may be solution treatment at 480-545 DEG C., followed by precipitation hardening for a time H (in hours) at a temperature T (in DEG C.) given by the formulae (1) where Cu initially in solution exceeds 4.5 per cent.: <FORM:0709527/II/1> (2) where Cu initially in solution is 3.5-4.5 per cent.: <FORM:0709527/II/2> (3) where Cu initially in solution is less than 3.5 per cent.: <FORM:0709527/II/3> X being any value between 2 and 20. Working may be carried out following solution treatment at any temperature between room temperature and the solidus temperature of the alloy disregarding any cadmium-rich constituent present. According to the first Provisional Specification, the content of Cd may be up to 1 per cent. Mg up to 0.5 per cent., and Si up to 16 per cent.