Abstract: A carbon nanotube composite material (1) includes a metal base material (10) and carbon nanotube electrically-conductive path portions (20). The metal base material (10) is made from a polycrystalline substance in which a plurality of rod-shaped metal crystal grains (11) are oriented in a direction. The carbon nanotube electrically-conductive path portions (20) are made from doped carbon nanotubes having a dopant, existing in parts of grain boundaries (15) between the rod-shaped metal crystal grains (11) in a cross section of the metal base material (10), and forming an electrically-conductive path which is electrically conductive in a longitudinal direction of the metal base material (10), by existing along the longitudinal direction (L).

Abstract: To provide a metal wire and an electric wire of high mechanical strength and high ductibility that have sufficiently increased ductibility as well as sufficiently increased mechanical strength. A metal wire manufactured at least by being subjected to an extension in which a metal wire is extended in an axial direction, and having a hardness distribution in which hardness decreases toward a specific peripheral portion from a central portion in a cross-section orthogonal to axis, whereby a softened peripheral portion becomes to show a good malleability as well as a high resistance to cracking, so as to attain an improvement of mechanical strength and ductibility.

Abstract: A carbon nanotube composite material (1) includes a metal base material (10) and carbon nanotube electrically-conductive path portions (20). The metal base material (10) is made from a polycrystalline substance in which a plurality of rod-shaped metal crystal grains (11) are oriented in a direction. The carbon nanotube electrically-conductive path portions (20) are made from doped carbon nanotubes having a dopant, existing in parts of grain boundaries (15) between the rod-shaped metal crystal grains (11) in a cross section of the metal base material (10), and forming an electrically-conductive path which is electrically conductive in a longitudinal direction of the metal base material (10), by existing along the longitudinal direction (L).

Abstract: To provide a metal wire and an electric wire of high mechanical strength and high ductibility that have sufficiently increased ductibility as well as sufficiently increased mechanical strength. A metal wire manufactured at least by being subjected to an extension in which a metal wire is extended in an axial direction, and having a hardness distribution in which hardness decreases toward a specific peripheral portion from a central portion in a cross-section orthogonal to axis, whereby a softened peripheral portion becomes to show a good malleability as well as a high resistance to cracking, so as to attain an improvement of mechanical strength and ductibility.

Abstract: An ultrasonic joining method and apparatus is provided, by which a large joined area can be obtained in a short period of operating time without damage. The ultrasonic joining apparatus includes a chip and an anvil, between which the first conductor of the first flexible flat cable and the second conductor of the second flexible flat cable as an object to be joined are put. An end surface of the chip facing the anvil is formed flat. The end surface is provided with a plurality of the first straight grooves. The first straight groove is formed extending straight. The plurality of the first straight grooves are arranged in parallel with each other.