HIGH TEMPERATURE STABLE ALUMINIUM ALLOY

摘要

The present invention relates to Al-Mg-Si-Cu alloy optimised for high temperature stability The alloy is characterized in that its content of Mg and Si lies within a polygon defined by the following coordinates of an Mg-Si diagram: a1 - a2 - a3 - a4 -a1 where in wt.% a1 = 0.60Mg,0.60Si, a2 = 0.90Mg, 0.90Si, a3 = 1.30 Mg, 0.60 Si and a4 = LOOMg, 0.30Si, and with the additional alloying elements: - Cu between 0.20 and 0.50 wt.% - Fe between 0.08 and 0.40 wt.%, and where at least one of the following elements are added for the purpose of grain structure control during processing of the alloy - Mn between 0 and 0.80 wt.% - Cr between 0 and 0.30 wt.% - Zr between 0 and 0.30 wt.%, and optionally Ti up to 0, 1 wt% and B up to 0,1 wt% as grain refining elements, and further optionally Ge between 0 and 0.20 wt.% and Ag between 0 and 0.20 wt.%, rest Al, including incidental impurities. In the alloy as defined above the L-phase is the dominant precipitate type as regards number density upon over-ageing.