| 摘要 |
PCT No. PCT/JP92/00414 Sec. 371 Date Dec. 3, 1992 Sec. 102(e) Date Dec. 3, 1992 PCT Filed Apr. 3, 1992 PCT Pub. No. WO92/17302 PCT Pub. Date Oct. 15, 1992.The rapidly solidified aluminum alloy powder is preformed in a cold or warm environment to form a powder compact having a relative density of 75-93%. Then, the preformed compact is heated and degassed in the atmosphere of an inert gas at temperature of 300 DEG C. to 560 DEG C. for 0.25-3 hours. Immediately thereafter, the compact is subjected to hot coining at 300 DEG -560 DEG C. to obtain a solidified compact having pores at a rate of 2-5%. The solidified compact is then subjected to sizing. Since the inorganic gas prevents reaction between the evaporated water and aluminum while preheating the compact, the hot coining can be carried out in a state where solid state diffusion easily occurs. Thus, the powder particles can be bonded together strongly with a single forging. Also, at the end of hot coining, pores remain in the solidified compact at the rate of 2-5%. Utilizing these pores, the compact can be subjected to sizing to improve its dimensional accuracy. The rotor for an oil pump thus formed can withstand use at high temperatures.
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