An exemplary embodiment of the present invention provides a coated steel sheet on which a magnesium-aluminum alloy coating layer is formed, including: a steel sheet; and a coating layer configured to include a first magnesium-aluminum alloy layer formed on a top surface of the steel sheet and a second magnesium-aluminum alloy layer formed on a top surface of the first magnesium-aluminum alloy layer, wherein a magnesium content of the first magnesium-aluminum alloy layer is higher than that of the second magnesium-aluminum alloy layer.

An engineered composite system designed to be passive or inert under one set of conditions, but becomes active when exposed to a second set of conditions. This system can include a dissolving or disintegrating core, and a surface coating that has higher strength or which only dissolves under certain temperature and pH conditions, or in selected fluids. These reactive materials are useful for oil and gas completions and well stimulation processes, enhanced oil and gas recovery operations, as well as in defensive and mining applications requiring high energy density and good mechanical properties, but which can be stored and used for long periods of time without degradation.

A method of manufacturing a low-density clad steel sheet, including: preparing a base material, a lightweight steel sheet including C: 0.3 to 1.0%, Mn: 4.0 to 16.0%, Al: 4.5 to 9.0%, and Fe; preparing cladding materials, each being martensitic carbon steel including C: 0.1 to 0.45%, Mn: 0.1 to 3.0%, and Fe; disposing the base material between the cladding materials to obtain a laminate; welding an edge of the laminate, and heating the welded laminate to 1050 to 1350? C.; finish-rolling the heated laminate to 750 to 1050? C. with a rolling reduction ratio of 30% or more in a first pass, to obtain a hot-rolled steel sheet; coiling the hot-rolled steel sheet at 400 to 700? C.; applying a cold-reduction ratio of 35 to 90% to obtain a cold-rolled steel sheet; and annealing the cold-rolled steel sheet at 550? C. or higher and A3+200? C. or lower of the cladding materials.

A metallic flat product is disclosed which is subjected to surface finishing by hot-dip coating and which is preferably composed of steel. The metallic flat product includes a metallic alloy layer (11) and a metallic surface layer (12), which metallic alloy layer and metallic surface layer differ from one another in terms of their chemical composition. The two layers (11, 12) are produced in a one process step and define a continuous transition region (13) in which a mixture of the two different chemical compositions is present. The metallic alloy layer (11) has a thickness of less than 8 m, preferably less than 6 m, and the surface layer (12) is formed from aluminum or zinc. The flat product has an improved coating, by means of which the flat product more effectively satisfies the requirements with regard to good deformability and has good anti-corrosion protection.

An Mg-containing Zn alloy coated steel including a steel and a metallic coating layer placed on a surface of the steel, in which the metallic coating layer is a layered structure of a flat-form metal particle having a particle diameter of from 5 to 100 m, and a thickness of from 0.5 to 30 m, the composition of the metal particles include, in terms of % by mass, Zn from 11 to 80%, Al from 3 to 80%, Mg from 8 to 45%, and Ca from 1 to 5%, while the balance is impurities, and the Zn content, the Al content, and the Mg content in terms of % by mass satisfy Zn+Al>Mg, and in which the metal particles include a quasicrystalline phase, an MgZn.sub.2 phase, and a balance structure, in which the total area fraction of the quasicrystalline phase and the MgZn.sub.2 phase is 45% or more, the area fraction of the balance structure is from 0 to 55%, the area fraction of the quasicrystalline phase is 20% or more, and the area fraction of the MgZn.sub.2 phase is 3% or more.

An embodiment relates to a method comprising overmolding a bulk-solidifying amorphous alloy on a preform of another material than the bulk-solidifying amorphous alloy to form a bulk-solidifying amorphous alloy overmolded preform. Another embodiment relates to an article comprising an overmolded shell comprising the bulk-solidifying amorphous alloy on a preform of another material than the bulk-solidifying amorphous alloy. The preform could be made of a crystalline or amorphous metal or alloy such as aluminum, stainless steel, copper or beryllium.

The invention provides a coated steel including a steel, a coated metal layer coated on a surface of the steel, and an interfacial alloy layer formed at the boundary between the steel and the coated metal layer, in which the composition of the coated metal layer includes in terms of % by mass Zn from 20 to 83%, and Al from 2.5 to 46.5% as well as Mg and impurities as the balance, in which the Mg content is 10% or more, in which the structure of the coated metal layer includes a quasicrystalline phase, a MgZn.sub.2 phase, and a balance structure, in which the area fraction of the quasicrystalline phase is from 30 to 60%, and not less than 90 number-% of the quasicrystalline phases are a quasicrystalline phase having a particle diameter in the major axis direction of from 0.05 to 1.0 m, and in which the thickness of the coated metal layer is 0.1 m or more, and the thickness of the interfacial alloy layer is 500 nm or less.

[Object] To provide a quasicrystal-containing plated steel sheet having a good balance between corrosion resistance and chipping resistance and a method for producing the quasicrystal-containing plated steel sheet.

[Solution] Provided is a quasicrystal-containing plated steel sheet including: a plating layer positioned on at least one surface of a steel sheet; and an alloy layer positioned at an interface between the plating layer and the steel sheet and composed of an AlFe intermetallic compound. A chemical composition of the plating layer contains at least, in atom %, Zn: 28.5% to 50%, Al: 0.3% to 12%, and the balance: Mg and impurities, and the plating layer includes, in order from the steel sheet side, a first plating layer which is composed of a structure containing an MgZn phase, an Mg phase, and a quasicrystal phase, and a second plating layer which is positioned on the first plating layer and is composed of a structure containing an Mg.sub.51Zn.sub.20 phase, a Zn phase, and a quasicrystal phase.

A metallic structure includes a first plurality of metal particles arranged in an amorphous structure; a second plurality of metal particles arranged in a crystalline structure having at least two grain sizes, wherein the crystalline structure is arranged to receive the amorphous structure deposited thereon; wherein the grain size is arranged in a gradient structure.

In a process for friction stir welding together pieces of dissimilar material, a first piece of a second metal is overlaid onto a first piece of a first metal that is dissimilar from the second metal such that at least a portion of the first piece of second metal overlaps a portion of the first piece of first metal. The first piece of second metal has a plurality of holes therein and the holes are disposed in overlapping relationship with the portion of the first piece of first metal. Each of the holes is filled with a plug formed from the first metal. The first piece of first metal is friction stir welded to the first piece of second metal at each of the plug locations.