PURPOSE: To provide an Al-matrix composite material excellent in adhesion resistance and suitable for production of a wear resistant annular part by incorporating specific amounts of primary-crystal Si grains and eutectic Si grains, having fine grain sizes, into an Al type matrix.
CONSTITUTION: The Al-matrix composite material is formed by incorporating primary-crystal Si grains and eutectic Si grains, having ≤20μm average grain size, into an Al type matrix by 20-36vol.%. In this composite material, the Al type matrix contains, according to purposes, a first Si grain of 3-10μm average grain size, a second Si grain consisting of eutectic Si of ≤1μm, and a third Si grain of 20-60μm average grain size, and further, the first Si grain and the second Si grain are contained by 20-40%, respectively, and the third Si grain is contained by 1-6%. This Al type composite material is used, e.g. for a component material for an annular reinforcing part 51 connected to the piston head 50a side, in a piston body 50 of a piston 5.
SUGANUMA TETSUYA
OKOCHI YUKIO
