Abstract: A 5000-series aluminum alloy expanded material which does not undergo the occurrence of welding cracks even when the aluminum alloy expanded material is subjected to high-speed welding utilizing laser welding or the like; a welding-joined body comprising the aluminum alloy expanded material; and a method for efficiently welding the aluminum alloy expanded material. An aluminum alloy expanded material for welding use, which is characterized by having an Mg content of 0.2% by mass or more and less than 6.0% by mass, and containing a surface active element capable of reducing the surface tension of molten aluminum, in which the surface active element comprises at least one element selected from Sr, Ca, Sb, Li and Ba, and the content of the surface active element is 0.08 to 0.50% by mass inclusive.

Abstract: A wrought 6000-series aluminum alloy material which is suppressed in weld cracking even in cases where high-speed welding is performed by means of laser welding or the like; a welded body which contains the wrought aluminum alloy material; and an efficient welding method for the wrought aluminum alloy material. A wrought aluminum alloy material for welding, the wrought aluminum alloy material being characterized in that: the Si content is not less than 0.3% by mass but less than 2.0% by mass; the Mg content is not less than 0.3% by mass but less than 2.0% by mass; a surface active element which decreases the surface tension of molten aluminum is contained therein; the surface active element is at least one of Sr, Ca, Sb, Li and Ba; and the content of the surface active element is from 0.04% by mass to 0.50% by mass.

Abstract: Provided are: an aluminum alloy filler material which is less likely to cause welding cracks and from which a joint portion having excellent strength and toughness is formed, in high-speed joining of an aluminum alloy; an aluminum alloy welded structure manufactured using the aluminum alloy filler material; and a method for joining an aluminum material using the aluminum alloy filler material. The aluminum alloy filler material for high-speed joining according to the present invention is characterized by comprising aluminum including a surface-active element that lowers the surface tension of molten aluminum, wherein the surface-active element is at least one among Ca, Sr, and Ba, and the content of the surface-active element is 0.05-0.50 mass %.

Abstract: Provided are a 6000-series aluminum alloy forging material having high strength and exceptional toughness (excellent ductility), and an efficient method for manufacturing the same. This aluminum alloy forging material is characterized by being formed from a 6000-series aluminum alloy, having a Cu content of 0.2-1.0 wt. %, the composition of the 6000-series aluminum alloy satisfying relational expressions (1) and (2), and having deposits at the base metal crystal grain boundary, specifically Al—(Fe,Mn,Cr)—Si-type crystalline deposits at the base metal crystal grain boundary. (1) Si (at %)?2Mg (at %) and (2) 0.2?surplus Si (wt %)+Mn (wt %)+Cr (wt %)?1.7.