Method and arrangement for producing a three-dimensional material composite using an expansion body

A method for producing a three-dimensional material composite of at least two metal bodies, wherein the metal bodies are initially assembled such that the surface areas to be connected loosely abut on one another, wherein said composite is then heated to a target temperature while said surface areas are pressed against one another such that no gap remains, and wherein a positive-locking and/or firmly bonded connection is produced between the surface areas of the metal bodies,

• wherein the pressure required for pressing the surface areas against one another is generated by arranging at least one expansion cavity with a predefined initial volume in one of the metal bodies or in an additional expansion body, which abuts on at least one of the metal bodies, in such a way that, during its expansion, the surface areas to be connected are pressed against one another,
• wherein a predefined amount of at least one substance is filled into the expansion cavity and hermetically confined, wherein said substance is gaseous at least at the target temperature or forms, prior to reaching the target temperature, at least one substance in a predefined proportion that is gaseous at the target temperature, wherein the inner wall of the expansion cavity consists of a material that cannot absorb the at least one gaseous substance and cannot react therewith such that the amount of the at least one gaseous substance changes,
• wherein the predefined amount of substance is chosen in such a way that a predefined pressure is reached in the expansion cavity upon reaching the target temperature, and wherein this predefined pressure suffices for closing any existing gaps between the surface areas to be connected due to a deformation of the metal body containing the expansion cavity or the expansion body, respectively, and at least one of the abutting metal bodies.