HIGH-STRENGTH ALUMINUM-ALLOY EXTRUDED MATERIAL EXCELLENT IN LOW-CYCLE FATIGUE CHARACTERISTICS

摘要

PURPOSE:To obtain a high-strength Al-alloy extruded material excellent in low-cycle fatigue characteristics by incorporating specific percentage of Zn, Fe, Mg and Si to Al. CONSTITUTION:An Al alloy consisting of, by weight, 5.0-10% Zn, 0.25-1.0% Fe, 0.5-3.6% Mg, Si in an amount limited to =0.20% and the balance Al with inevitable impurities and containing, if necessary, 1 or =2 kinds among =0.4% Mn, =0.3% Cr, =0.3% Zr, =0.5% Ti and =0.05% B is prepared. In this way, the Al-alloy extruded material combining high strength with high toughness, increased in resistance to local brittle fracture which occurs when subjected to light load and also increased in low-cycle fatigue strength can be obtained.