| 摘要 |
PROBLEM TO BE SOLVED: To provide a long-life product, for example, a cylinder block, by, using a metallic porous preform excellent in abrasion resistance at a region especially severe in abrasion breakage, and to provide a production method thereof. SOLUTION: A metallic porous sheet, discontinuously having two or more areas different in the ratio of volume or material qualities, is formed by superimposing one or more metallic porous sheets 2 on a partial area of a different metallic porous sheet 1, and thereafter making the all area with the same thickness by rolling-pressurizing or plane-pressurizing. Thereafter, a metallic porous preform 4 of cylindrical shape is produced by bend-working. This preform 4 is internally chilled to form a composite member by setting it in a metal mold and pouring an aluminum alloy molten metal thereto.
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