A sealant for a weld joint and an associated weld joint and method are provided. The sealant includes aluminum and germanium and is characterized by a melting temperature that is lower than the melting temperature of the structural member that is joined. The sealant, which is disposed between faying surfaces of the structural members, can fill the spaces between the structural members to prevent the entry of chemicals, moisture, debris, and other substances, thereby reducing the likelihood of corrosion of the joint or structural members at the interface. Further, the sealant can be diffusion bonded to the faying surfaces, for example, by the heat generated during the joining process
