Patent ID: 7514155

Claim:
High strength aluminium alloy brazing sheet, comprising: an Al—Cu core layer consisting essentially of the following core layer composition (in weight percent): Cu: 1.2 to 2.5 Mn: 0.06 to 0.45 Mg: 0.06 to 1.5 Si: 0.1 to 0.25 Zn: <0.4 Fe: <0.5, and optionally one or more of: Zr: <0.25 Cr: <0.25 V: <0.25 Ti: <0.25, the balance aluminium and incidental elements and impurities, a clad layer having a clad layer composition comprising an Al—Si based filler alloy and being respectively applied on each side of the core layer, and an interlayer having an interlayer composition comprising either an Al—Mn alloy composition of the AA3xxx-type or an AlMgSi alloy of the AA6xxx-type, on at least one side of the core layer, the interlayer comprising either a sacrificial anode material which is less corrosion resistant than the core layer or a protective material which is more corrosion resistant than the core layer, and having a corrosion potential difference against the core layer as measured according to ASTM G69 of at least 10 mV versus SCE, wherein if the interlayer comprises the Al—Mn alloy composition, the interlayer Al—Mn alloy composition consists essentially of the following composition (in weight percent): Mn: 0.8 to 1.5 Zn 0.5 to 2.5 Si: <0.5 Cu: <0.5 Mg: <0.3 Fe: <0.5 Ti: <0.2, the balance aluminium and incidental elements and impurities.