According to the present invention, provided are a joint structure (100) which joins a plurality of overlapped steel members (110, 120) using a connecting element (130) having a shaft portion (131), the joint structure including: a first steel member (110); and one or more of second steel members (120) overlapping the first steel member (110), in which the shaft portion (131) of the connecting element (130) is penetrated through the second steel member (120), and the shaft portion (131) of the connecting element (130) and the second steel member (120) are joined by friction welding, and the shaft portion (131) and the first steel member (110) are joined by friction welding, and a joining method for obtaining the joint structure.

An apparatus and method for fastening dissimilar materials like steel, plastic and aluminum. A resistance welding fastener having multiple layers may be used with or without a sealant. The fastener may be used to form an aluminum covered steel laminate via a hemming pattern of attachment. The fastener may have a solid shaft or have an extended reach and have features for interacting with the welding electrode. A variety of electrode tips may be employed to cooperate with the fastener.

Shear assisted extrusion processes (ShAPE) for forming Metal-NCCF extrusions are provided. The processes can include: using a die tool, applying a rotational shearing force and an axial extrusion force to a feedstock material comprising a metal and NCCF (NanoCrystalline Carbon Films); and extruding a mixture comprising the metal and NCCF through an opening in the die tool to form the Metal-NCCF extrusion. ShAPE feedstock materials are provided that can include a metal and NCCF. Conductive solid material mixtures are provided that can include a metal and a NCCF. Portions of the metals and NCCF of the material mixtures can have an isotropic crystallographic orientation. Assemblies relying in part on conductivity can include: a conductive solid material mixture that includes: a metal; and a NCCF.

A dissimilar metal article may include a first metallic component including a first metal material, a second metallic component comprising a second metal material, and a transition joint provided between and bonding a first metallic component first end surface to a second metallic component first end surface. An additive flow material may be further provided to the dissimilar metal article to strengthen the joint between the first metallic component and the second metallic component.