| 摘要 |
A valve spring retainer for a valve operating mechanism for an internal combustion engine comprises a matrix formed from a quenched and solidified aluminum alloy powder, and a hard grain dispersed in said matrix. The hard grain is at least one selected from the group consisting of grains of Al2O3, SiC, Si3N4, ZrO2, SiO2, TiO2, Al2O3-SiO2 and metal Si. The amount of hard grain added is in a range of 0.5% to 20% by weight, and the area rate of said hard grain is in a range of from 1% to 6%.
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