Compound material and method for heat treating the same

Heat treating composite material comprising a curable base material based on aluminum-zinc-magnesium alloy, and a non-curable plating based on aluminum-zinc alloy, comprises carrying out at least regional solution annealing, preferably accelerating, cooling and aging the composite material. The base material comprises a mixed crystal matrix depleted at zinc by natural aging, preferably by forming magnesium-zinc (MgZn 2) phases, and exhibits noble properties such that an electrochemical potential difference of 40-130 mV is adjusted between the plating and the base material. Heat treating a composite material comprising a curable base material based on aluminum-zinc-magnesium alloy, and a non-curable plating based on aluminum-zinc alloy, provided on the base material, comprises carrying out at least partial solution annealing, preferably accelerating, cooling and aging the composite material. The base material comprises a mixed crystal matrix which is depleted at zinc by natural aging, preferably by forming magnesium-zinc (MgZn 2) phases, and exhibits noble properties such that an electrochemical potential difference of 40-130 mV is adjusted between the plating and the base material which is nobler compared to the plating. Independent claims are also included for: (1) the composite material, preferably aluminum-based plated sheet metal, comprising the base material which comprises 1-2 wt.% magnesium, 2-4.5 wt.% zinc, optionally not > 0.3 wt.% copper, up to 0.4 wt.% iron, up to 0.35 wt.% silicon, up to 0.5 wt.% manganese and/or up to 0.35 wt.% chromium and remaining amount of aluminum and production-related impurities, and the plating which comprises 2-5 wt.% zinc, optionally not > 0.3 wt.% magnesium, up to 0.1 wt.% iron, up to 0.1 wt.% silicon and/or up to 0.2 wt.% chromium, zirconium, scandium, hafnium, vanadium and/or silver, and remaining amount of aluminum and production-related impurities; and (2) use of the composite material, preferably aluminum-based plated sheet metal for soldering or welding with a subsequent natural aging, where the contents of magnesium and zinc are adjusted in the base material such that the noble base material leads to an electrochemical potential difference between plating and the base material which is nobler compared to the plating, of 40-130 mV due to cold-curing-related depletion of its mixed crystal matrix at zinc by forming magnesium-zinc (MgZn 2) phases. Es wird ein Verbundwerkstoff und ein Verfahren zur Wärmebehandlung