Al-Cu BASED ALUMINUM ALLOY FORGED OBJECT

摘要

PROBLEM TO BE SOLVED: To provide an Al-Cu based aluminum alloy forged material which prevents coarse crystal grains during solution treatment after free forging and has excellent heat resistance and strength.SOLUTION: An Al-Cu based aluminum alloy is manufactured by free forging. In the Al-Cu based aluminum alloy, when a series of hot free forging processes to be started after a material is heated at a temperature of 400°C or more includes a partial large-strain forging process wherein the material is forged while a compressed strain rate on at least a part of the whole forged object exceeds 50%, a series of hot free forging processes is terminated by performing partial large-strain forging while a part of the material to be applied with at least partial large-strain is maintained at a temperature of 400°C or more. Then, a microstructure of the forged object after a solution treatment process for heating and maintaining the forged object and a subsequent quenching treatment process for rapidly quenching the forged object is a hot processed structure including minute sub-grains of an average grain size of 30 μm or below.