再时效处理对2219-T6铝合金叉形环显微组织和力学性能的影响

Effect of reaging on microstructures and mechanical properties of 2219-T6 alloy fork-like ring

通过扫描电镜(SEM)、透射电镜(TEM)和室温拉伸性能测试等分析方法,研究再时效处理对2219-T6铝合金叉形环显微组织与力学性能的影响。结果表明:在170℃下再时效12 h时,构件抗拉强度达到406 MPa,屈服强度达到314 MPa,伸长率为8%,其力学性能和成形性的综合效果最佳。延长时效时间,与(170℃,12 h)时效态相比,第二相粒子出现明显的团聚现象,晶界无析出带(PFZ)宽度增加,合金中析出相长宽比减小,θ″相含量下降,大部分转变成亚稳相θ′,部分生成粗大的平衡相θ,其力学性能明显下降。

The effects of reaging on the microstructures and mechanical properties of 2219-T6 alloy fork-like ring were investigated by tensile test, scanning electron microcopy（SEM） and transmission electron microscopy（TEM）. The results show that after reaging at 170 ℃ for 12 h, the tensile strength, yield strength and elongation of the fork-like ring are 406 MPa, 314 MPa, 8%, respectively. Increasing the aging time, the mechanical properties of the alloy has fallen greatly because of denser precipitates and wide precipitate free zones（PFZ）. Compared to aging treatment（170 ℃, 12 h）, the aspect ratio of precipitates decreases and large number of θ″ precipitates transform into θ′ precipitates, some of that become thick θ precipitate.