Brazed structure

A brazed joint structure, comprising

• a brazing sheet which has been brazed and which comprises
• a core material comprising an aluminum alloy, and
• a brazing filler material comprising an Al—Si alloy and being clad to at least one surface of the core material,
• wherein
• the brazing filler material is clad in a thickness of 15 μm or more and in a clad ratio of from 1 to 25% per surface,
• the aluminum alloy of the core material comprises
• Si in an amount of more than 0.3 mass % and 1.0 mass % or less,
• Mn in an amount of 0.7 mass % or more and 2.0 mass % or less,
• Cu in an amount of more than 0.3 mass % and 1.0 mass % or less,
• Mg in an amount of more than 0.15 mass % and 0.5 mass % or less, and
• Al,
• wherein the core material has an average grain size of 50 μm or more, and
• wherein an occupancy of an Mg—Si intermetallic compound and an Al—Mg—Si—Cu intermetallic compound that are present in a grain boundary of the core material is 23% or less.