Abstract: The tests are made to produce a kind of cast Al-Si alloy with high strength and heat-resistance;Its cast properites are measured and the appropriate parameters of heat treat-ment process are determined. The microstructure,the enhancing and heat-resisting mechanicsm of the alloy are analysed.The development alloy possesses fine cast properties, its mechanical properties:σb≥300MPa。δ≥3% at room temperature;σb≥200MPa,δ≥4% at 250℃ after 30 minutes.The alloy can be used to produce the casting ofmissile hull ofhigher perfonnance.

Key words: aluminum alloy, chemical composition, cast alloys