| 摘要 |
PURPOSE:To improve strength after superplastic working by subjecting an ingot of Al-Cu alloy in which Cr, Mn, and Zr are added to homogenizing heat treatment, hot rolling, heating and holding, and cooling under respectively speci fied conditions and then carrying out cold working while performing intermedi ate heating between the cold working stages. CONSTITUTION:An Al alloy which has a composition consisting of, by weight, 0.5-7% Cu, further one or more kinds among 0.05-0.5% Cr, 0.05-0.5% Mn, and 0.05-0.5% Zr, as essential element and the balance Al with impurities and containing, if necessary, one or more kinds among 0.5-4% Li, <=2.5% Mg, 0.05-0.5% V, and <=0.15% Ti is cast. The resulting ingot is subjected to homoge nizing heat treatment at 300-550 deg.C for 6-48hr and to hot rolling at 300-550 deg.C. Subsequently, the above alloy is subjected to heating and holding by a single or two stages at the above temp. and to cooling at >=30 deg.C/hr cooling rate. Then, the above alloy is cold-worked at least at >=50% draft, held at 450-550 deg.C for 10min-1hr at >=300 deg.C/hr heating rate, and cold-worked at >=4% draft. |
