(1. 中南大学 高性能复杂制造国家重点实验室，长沙 410083；
2. 中南大学 轻合金研究院，长沙 410083)
摘 要: 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。
关键字: 2219铝合金；叉形环；再时效；显微组织；力学性能
（1.State Key Laboratory of High Performance and Complex Manufacturing,
Central South University, Changsha 410083, China;
2. Light Alloy Research Institute, Central South University, Changsha 410083, China）
Abstract: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.
Key words: 2219 aluminum alloy; fork-like ring; reaging; microstructures; mechanical property
