(1. 中南大学 材料科学与工程学院，长沙 410083； 2. 中南大学 有色金属先进结构材料与制造协同创新中心，长沙 410083)
摘 要: 研究预变形量对经T9I6工艺处理的2519A铝合金组织和力学性能的影响。通过显微硬度测试、室温拉伸测试检测合金的室温力学性能，采用透射电镜(TEM)和高分辨透射电镜(HRTEM)分析合金的显微组织。结果表明：当预变形量为15%时，合金的屈服强度和抗拉强度取得最大值，分别为456.1 MPa和501.6 MPa，继续增大预变形量会导致强度下降；而合金的伸长率随着预变形量的增大而逐渐下降。2519A铝合金在T9I6工艺中强化方式主要为形变强化和析出强化；合金的形变强化效果随着预变形量的增大有增大的趋势，但提升幅度逐渐减小。预变形过程中引入的位错能够与合金在预时效阶段析出的GP区相互作用，从而改善位错分布。当预变形量增大时，基体内会发生回复作用导致位错密度减少，且后续时效过程中GP区析出被抑制，对强化相θ′相的形核产生不利影响，减弱析出强化的效果。
关键字: 2519A铝合金；断续时效；力学性能；显微组织；预变形
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China; 2. Key Laboratory of Nonferrous Materials Science and Engineering, Ministry of Education, Central South University, Changsha 410083, China）
Abstract:The effects of pre-deformation on microstructure and mechanical properties of T9I6 interrupted-aged 2519A aluminum alloy were investigated by transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), hardness tests and tensile tests. The results show that when the pre-deformation rate is 15%, both the yield strength and tensile strength of the alloy get their highest values, 456.1 MPa and 501.6 MPa, respectively. Further increasing the pre-deformation rate will decrease the strength. While the elongation decreases with increasing the pre-deformation rate. The mechanical properties of 2519A alunimiun in T9I6 treatment are contributed mainly by strain hardening and age hardening. The effect of strain hardening tends to increase with increasing the pre-deformation rate, but the rate of increase gradually reduces. The dislocation introduced by strain can interact with GP zones formed during pre-ageing and improve the distribution of dislocation. If the pre-deformation rate is too large, the occurring of recovery can decrease the density of dislocations. Also, the formation of GP zones in the following process will be inhibited, which can adversely affect the nucleation of θ′ precipitates and reduce the effect of age hardening.
Key words: 2519A aluminum alloy; T9I6 thermo-mechanical treatment; mechanical property; microstructure; pre-deformation
