Provided are embodiments of an aluminium composite material for use in thermal flux-free joining methods. The composite material has at least one core layer of an aluminium core alloy and at least one outer solder layer of an aluminium solder alloy. The aluminium solder alloy has the following composition in wt %: 6.5%≤Si≤13%, Fe≤1%, 230 ppm≤Mg≤450 ppm, Bi≤500 ppm, Mn≤0.15%, Cu≤0.3%, Zn≤3%, and Ti≤0.30% with the remainder Al and unavoidable impurities individually at most 0.05%, in total at most 0.15% and the aluminium solder layer has an alkaline pickled or acid pickled surface. The invention further relates to a method for producing an aluminium composite material, a method for the thermal joining of components, and a thermally joined construction.