PURPOSE: To manufacture the lightweight rotor material having high temp. strength and excellent wear resistance by mixing Al alloy powder contg. specified ratios of Si, Fe, Cu, Mn and Mg with specified amt. of MoS2 powder and sintering the mixture.

CONSTITUTION: Powder is manufactured from the ingot of an Al alloy contg., by weight, 14 to 30% Si, 0.2 to 8.0% Fe, 1.0 to 5.0% Cu, 0.3 to 1.0% Mn, 0.5 to 2.0% Mg and the balance Al with impurities by an atomizing method. The Al alloy powder is mixed with 0.5 to <5% MoS2 powder, which is deaerated by cold isotatic pressing and is thereafter formed by hot pressing. In this way, the rotor material having good mechanical workability such as machinability can be obtd., which is preferably suitable as the rotor material of a compressor for a car cooler.