| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to easily bend a hollow material by arranging a metallic body for foaming in this hollow material to cause foaming by heating and volumetric expansion thereof supporting the hollow material from its inside with the foamed metallic body and subjecting the material to bending. SOLUTION: The metallic body 2 for foaming in an unfoamed state is arranged within the straight tubular hollow material l and is heated. The foaming and volumetric expansion of the metallic body 2 for foaming occur and the porous metallic body 2' contg. many cells is obtd. The porous metallic body 2' comes into tight contact with the inside surface of the hollow material 1 and supports the hollow material 1 from the inside. The hollow material 1 is subjected to bending and is formed to a bent article 3. The bending may be executed without the collapse at the bent part. The hollow material 1 is preferably an aluminum extrudate. The metallic body 2 for foaming is preferably formed by extruding a mixture composed of Al powder and TiH2 powder and solidifying the extrudate. When the metallic body 2 for foaming is heated to >=480 deg.C, its volume is expanded by foaming. The porous aluminum has a density of 0.1 to 0.5 g/cm3, is extremely light in weight and is capable of maintaining the lightness in weight of the bent article 3.
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