固溶时间对2219铝合金组织和力学性能的影响

Effect of solution time on microstructure and mechanical properties of 2219 aluminum alloy

通过力学性能测试、扫描电镜(SEM)、示差扫描量热法(DSC)和XRD分析等方法,研究固溶时间对2219铝合金组织和力学性能的影响。结果表明,当固溶温度为535℃,固溶时间不超过1.5 h时,随着固溶时间的延长,基体中含Cu结晶相回溶至基体,且不发生偏聚,提高了基体的过饱和度,有利于合金力学性能的提高;当固溶时间超过2 h时,含Cu结晶相发生偏聚长大,导致合金的力学性能特别是伸长率下降。因此,当固溶温度为535℃时,该合金适宜的固溶时间为1.5 h,之后经过(175℃×18 h)时效处理后,合金的抗拉强度R_(m)、屈服强度R_(p0.2)和断后伸长率A分别为393.5 MPa、305.9 MPa和8.7%。

Effect of solution time on microstructure and mechanical properties of 2219 aluminum alloy was studied by means of mechanical properties testing,scanning electron microscope(SEM),differential scanning calorimetry(DSC) and XRD analysis.The results show that,when the solution time is less than 1.5 h at 535 ℃,the primary phases dissolve in matrix and improve the supersaturation of the matrix with the solution time increasing,which is conducive to the improvement of mechanical properties of the alloy.When the solution time exceeds 2 h,the Cu-rich phases undergo segregation and grow up,resulting in the decrease of mechanical properties,especially elongation of the alloy.Therefore,the suitable solution treatment time of the alloy is 1.5 h at 535 ℃.After peak aging at 175 ℃ for 18 h,the ultimate tensile strength,yield strength and elongation of the aluminum alloy are 393.5 MPa、305.9 MPa and 8.7%,respectively.