HEAT RESISTANT Al BASE ALLOY EXCELLING IN HIGH-TEMPERATURE FATIGUE PROPERTY, DUMPING PROPERTY, ABRASION RESISTANCE AND WORKABILITY

摘要

A heat resistant Al base alloy that is lightweight and excels in not only high-temperature toughness and abrasion resistance but also high-temperature fatigue property, workability and dumping property. There is provided a heat resistant Al base alloy comprising an Al base alloy structure composed of 50 to 90 vol.% of intermetallic compound phase and the balance of metallic Al matrix, wherein the intermetallic compound constituting the intermetallic compound phase has an average size of ≤ 7 μm, preferably ≤ 5 μm, and wherein ≥ 50% of intermetallic compound of ≥ 0.5 μm particle diameter present in the visual field consists of an intermetallic compound with surface rugged configuration satisfying the relationship L2/S ≥ 13 in which S represents the area of intermetallic compound and L the peripheral length of intermetallic compound. Further, there is provided a heat resistant Al base alloy wherein when the structure is observed through a 500-magnification scanning electron microscope, the average of maximum length of metallic Al pool partitioned by the intermetallic compound phase is ≤ 40 μm, or wherein further solid dissolution of Cr, Fe and Ti in the metallic Al is effected in a total amount of 0.02 to 10%. Still further, there is provided a heat resistant Al base alloy wherein the ratio between total Al quantity in residue and total Al content in constituent composition, total Al quantity/total Al content, is ≤ 0.75, restricting the proportion of intermetallic compound of ≥ 0.1 μm size in the intermetallic compound phase.