An aspect of the present disclosure is to provide a method for manufacturing a welded structure capable of effectively suppressing welding LME cracks generated during spot welding of a zinc plated steel sheet having ultra-high strength, and a welded structure manufactured using the same.

An alloy for structural direct-writing additive manufacturing comprising a base element selected from the group consisting of aluminum (Al), nickel (Ni) and a combination thereof, and a rare earth element selected from the group consisting of cerium (Ce), lanthanide (La) and a combination thereof, and a eutectic intermetallic present in said alloy in an amount ranging from about 0.5 wt. % to 7.5 wt. %. The invention is also directed to a method of structural direct-write additive manufacturing using the above-described alloy, as well as 3D objects produced by the method. The invention is also directed to methods of producing the above-described alloy.

An alloy for structural direct-writing additive manufacturing comprising a base element selected from the group consisting of aluminum (Al), nickel (Ni) and a combination thereof, and a rare earth element selected from the group consisting of cerium (Ce), lanthanide (La) and a combination thereof, and a eutectic intermetallic present in said alloy in an amount ranging from about 0.5 wt. % to 7.5 wt. %. The invention is also directed to a method of structural direct-write additive manufacturing using the above-described alloy, as well as 3D objects produced by the method. The invention is also directed to methods of producing the above-described alloy.

In a mixed composition coating material for brazing, when a total mass of a solid material, an organic solvent, and water is defined as 100 mass %, the solid material are contained in an amount of 30 mass % or greater and 80 mass % or less with respect to the whole coating material, the organic solvent and the water is contained in a total amount of 20 mass % or greater and 70 mass % or less with respect to the whole coating material, and the water is contained in an amount of 0.4 mass % or greater and 2.5 mass % or less with respect to the whole coating material.

An electronic device includes a metal member and a connected member. A metal connecting layer is provided between a lower-side surface of the metal member and an upper-side surface of the connected member, to connect the metal member and the connected member to each other. The metal connecting layer includes at least one of metal films, each of which is made of gold or gold alloy. A thickness of the metal connecting layer in an opposing area between the metal member and the connected member is smaller than a flatness of each of the lower-side surface and the upper-side surface. A rust-preventing film is formed on a side wall of the metal member in such a way that the rust-preventing film extends from an outer periphery of the metal connecting layer to a position away from the outer periphery by a predetermined distance.

An electronic device includes a metal member and a connected member. A metal connecting layer is provided between a lower-side surface of the metal member and an upper-side surface of the connected member, to connect the metal member and the connected member to each other. The metal connecting layer includes at least one of metal films, each of which is made of gold or gold alloy. A thickness of the metal connecting layer in an opposing area between the metal member and the connected member is smaller than a flatness of each of the lower-side surface and the upper-side surface. A rust-preventing film is formed on a side wall of the metal member in such a way that the rust-preventing film extends from an outer periphery of the metal connecting layer to a position away from the outer periphery by a predetermined distance.

The application relates to an aluminum alloy hub and a method for coating the surface of the aluminum alloy hub. The aluminum alloy hub is provided with an aluminum alloy matrix and a coating attached to the surface of the aluminum alloy matrix, and the coating sequentially includes a pre-coating layer formed by nickel-coated aluminum or aluminum-coated nickel powder, a Cr.sub.3C.sub.2 layer and a varnish layer on the surface of the aluminum alloy matrix. According to the aluminum alloy hub disclosed by the invention, more excellent corrosion resistance is obtained by spraying the Cr.sub.3C.sub.2 layer on the surface of the aluminum alloy hub.

The application relates to an aluminum alloy hub and a method for coating the surface of the aluminum alloy hub. The aluminum alloy hub is provided with an aluminum alloy matrix and a coating attached to the surface of the aluminum alloy matrix, and the coating sequentially includes a pre-coating layer formed by nickel-coated aluminum or aluminum-coated nickel powder, a Cr.sub.3C.sub.2 layer and a varnish layer on the surface of the aluminum alloy matrix. According to the aluminum alloy hub disclosed by the invention, more excellent corrosion resistance is obtained by spraying the Cr.sub.3C.sub.2 layer on the surface of the aluminum alloy hub.

The present disclosure relates to a method of manufacturing an aluminum alloy with excellent mechanical properties by controlling a heat treatment step and a cooling step in a process of manufacturing the aluminum alloy. In detail, there is provided a method of manufacturing an aluminum alloy, including: a heating step of heating an aluminum alloy made of an aluminum alloy composite up to 500 to 560° C.; a solution treatment step of maintaining the heated aluminum alloy for 5 to 7 hours; a cooling step of cooling the solution-treated aluminum alloy for 15 seconds to 1 minute; and an aging step of age-hardening the cooled aluminum alloy for 2.5 to 4 hours at 140 to 180° C.

According to the method of manufacturing an aluminum alloy of the present disclosure and an aluminum alloy manufactured by the method, elongation is secured by reducing the solution treatment time and strength is increased by remaining heat by relatively increasing the drop speed of a pallet between a solution treatment furnace and a cooling container, the distance between the furnace and the container, and the cooling time, thereby being able to provide an aluminum alloy having excellent mechanical properties.

The present disclosure relates to a method of manufacturing an aluminum alloy with excellent mechanical properties by controlling a heat treatment step and a cooling step in a process of manufacturing the aluminum alloy. In detail, there is provided a method of manufacturing an aluminum alloy, including: a heating step of heating an aluminum alloy made of an aluminum alloy composite up to 500 to 560° C.; a solution treatment step of maintaining the heated aluminum alloy for 5 to 7 hours; a cooling step of cooling the solution-treated aluminum alloy for 15 seconds to 1 minute; and an aging step of age-hardening the cooled aluminum alloy for 2.5 to 4 hours at 140 to 180° C.

According to the method of manufacturing an aluminum alloy of the present disclosure and an aluminum alloy manufactured by the method, elongation is secured by reducing the solution treatment time and strength is increased by remaining heat by relatively increasing the drop speed of a pallet between a solution treatment furnace and a cooling container, the distance between the furnace and the container, and the cooling time, thereby being able to provide an aluminum alloy having excellent mechanical properties.