Abstract: Provided is a method of forming a sintered metal, the method including a first step of inserting tungsten (W) powder in a graphite mold, a second step of interposing tantalum (Ta) foil between the W powder and the graphite mold, and a third step of forming sintered W from the W powder through a sintering process.

Abstract: Provided is a cermet having improved toughness, the cermet including particles each of which has a complete solid-solution carbide of two or more metals selected, including titanium, from among Group IVa, Va, and VIa metals in the periodic table and has a core/rim structure composed of a core region and a rim region, and a binder composed of a metal, wherein the composition of the Group VIa metal in the core region is lower than the composition in the rim region, and the lattice constant in the rim region is larger than that in the core region.

Abstract: One embodiment of the present invention provides a sintering apparatus for selectively applying electric current, comprising: a mold provided with a space for accommodating a target object; a punch for uniaxially pressing the space of the mold; an electric controller provided at an end of the punch opposite to the pressing direction; an electrode unit in contact with the electric controller; and a heater extending from the electrode unit so as to heat the mold, wherein the mold and the punch are formed with a conductor.

Abstract: An electrically assisted pressure joining apparatus and an electrically assisted pressure joining method join a first metal member and a second metal member together, and includes an electrode portion, an intermediate portion including a plurality of micropores and inserted between a first metal member and a second metal member, and a pressure portion connected to the electrode portion to receive a current from the electrode portion and transfer the current to the first metal member and the second metal member to apply a pressure to the first metal member such that the first metal member and the second metal member are joined together by the intermediate portion.

Abstract: A method of joining a high entropy alloy is provided. The method of joining a high entropy alloy includes the steps of: arranging specimens made of a high entropy alloy to be in contact with each other; and diffusion joining the specimens made of the high entropy alloy by simultaneously applying a compressive stress and a current to a joint of the specimens within a range in which the high entropy alloy does not melt.

Abstract: Provided is a method for producing a metal sintered body. The method for producing a metal sintered body in accordance with an embodiment includes (a) disposing a metal powder in a chamber of a spark plasma sintering apparatus, (b) applying a electric current to the metal powder to raise a temperature inside the chamber from a standby temperature to a first sintering temperature, (c) lowering the temperature inside the chamber to a second sintering temperature lower than the first sintering temperature and performing sintering, and (d) lowering the temperature inside the chamber from the second sintering temperature to the standby temperature.

Abstract: Provided is a cermet having improved toughness, the cermet including particles each of which has a complete solid-solution carbide of two or more metals selected, including titanium, from among Group IVa, Va, and VIa metals in the periodic table and has a core/rim structure composed of a core region and a rim region, and a binder composed of a metal, wherein the composition of the Group VIa metal in the core region is lower than the composition in the rim region, and the lattice constant in the rim region is larger than that in the core region.

Abstract: Provided is a method for producing a metal sintered body. The method for producing a metal sintered body in accordance with an embodiment includes (a) disposing a metal powder in a chamber of a spark plasma sintering apparatus, (b) applying a electric current to the metal powder to raise a temperature inside the chamber from a standby temperature to a first sintering temperature, (c) lowering the temperature inside the chamber to a second sintering temperature lower than the first sintering temperature and performing sintering, and (d) lowering the temperature inside the chamber from the second sintering temperature to the standby temperature.

Abstract: Provided is a post-treatment method of a film-coated member, the method including heating an electrically conductive film provided on at least one surface of a substrate by applying pressure to a member including the substrate and the film and applying a high-frequency direct current pulse to the film, wherein the pressure is applied in a direction having a normal-vector-direction component of a layer of the film.

Abstract: Provided are a thin film structure capable of remarkably reducing the defect density of gallium nitride (GaN), and a method of fabricating the same. The thin film structure includes a supporting substrate including sapphire, and an epilayer disposed on the supporting substrate and including gallium nitride (GaN). An upper part of the supporting substrate facing the epilayer includes a layer of sapphire into which silicon (Si) is diffused or ion-implanted through a top surface of the supporting substrate.

Abstract: Provided are a thin film structure capable of remarkably reducing the defect density of gallium nitride (GaN), and a method of fabricating the same. The thin film structure includes a supporting substrate including sapphire, and an epilayer disposed on the supporting substrate and including gallium nitride (GaN). An upper part of the supporting substrate facing the epilayer includes a layer of sapphire into which silicon (Si) is diffused or ion-implanted through a top surface of the supporting substrate.

Abstract: An electrical transmission line for transmitting electricity is made of a composite material in which aluminum and a plurality of carbon nanotubes are combined, and a weight ratio of the carbon nanotubes to the aluminum is 0.5 to 3 wt %. The carbon nanotubes are oriented at an angle within 30° along a length direction of the electrical transmission line.

Abstract: An electrical transmission line for transmitting electricity is made of a composite material in which aluminum and a plurality of carbon nanotubes are combined, and a weight ratio of the carbon nanotubes to the aluminum is 0.5 to 3 wt %. The carbon nanotubes are oriented at an angle within 30° along a length direction of the electrical transmission line.

Abstract: Disclosed herein is a method for improving the formability of an aluminum alloy sheet by locally modifying the surface of the aluminum alloy sheet. The method comprises: a sheet fixing step of fixing a sheet to be locally surface-modified; and a local surface modification step comprising adhering a probe closely to a region of the fixed sheet, which is in need of surface modification, by the application of pressure, and then rotationally moving the probe on the region at high speed. According to the method, the region of the sheet in which a fracture can occur due to the concentration of strains and stresses during the formation of the aluminum alloy sheet into a product is subjected to local surface modification so as to improve the formability of the aluminum alloy sheet compared to the parent metal, so that the aluminum alloy sheet can be easily formed into a product.

Abstract: Disclosed herein is a method for improving the formability of an aluminum alloy sheet by locally modifying the surface of the aluminum alloy sheet. The method comprises: a sheet fixing step of fixing a sheet to be locally surface-modified; and a local surface modification step comprising adhering a probe closely to a region of the fixed sheet, which is in need of surface modification, by the application of pressure, and then rotationally moving the probe on the region at high speed. According to the method, the region of the sheet in which a fracture can occur due to the concentration of strains and stresses during the formation of the aluminum alloy sheet into a product is subjected to local surface modification so as to improve the formability of the aluminum alloy sheet compared to the parent metal, so that the aluminum alloy sheet can be easily formed into a product.

Abstract: Disclosed is a friction sheet welding method using a probe for joining two work pieces. The method comprises the steps of producing forcible and intense plastic deformation at surfaces of the work pieces while generating frictional heat at the surfaces by rotating the probe at a high speed, joining the work pieces together as the plastic deformation produced at the surfaces of the work pieces permeates inside material of the work pieces, and continuously welding the work pieces by horizontally traversing the probe along a weld joint between the work pieces.