| 摘要 |
PROBLEM TO BE SOLVED: To provide a precipitation-hardening Al alloy having well-balanced three properties, tensile strength, proof stress and elongation and also to provide a method for heat-treating precipitation-hardening alloys by which solution treatment can be performed at higher temperature while shortening temperature- rise time and reducing temperature deflection. SOLUTION: The precipitation-hardening Al alloy is obtained by heat-treating an Al alloy having forming strain and has a structure in which recrystallized grains and subgrains are formed and further has three characteristics of: >=320 MPa tensile strength, >=220 MPa 0.2% proof stress, and >=19% elongation; or >=350 MPa tensile strength, >=300 MPa 0.2% proof stress, and >=15% elongation. In the method for heat-treating the precipitation-hardening alloys, the precipitation-hardening alloys including the above Al alloy are subjected to solution treatment using a fluidized bed for <=60 min at a holding temperature ranging between a temperature lower by 10 deg.C and a temperature higher by 5 deg.C than the melting temperature of the alloy as the object to be heat-treated.
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