(1. 中南大學 材料科學與工程學院，長沙 410083； 2. 中南大學 有色金屬先進結(jié)構(gòu)材料與制造協(xié)同創(chuàng)新中心，長沙 410083)
摘 要: 研究預變形量對經(jīng)T9I6工藝處理的2519A鋁合金組織和力學性能的影響。通過顯微硬度測試、室溫拉伸測試檢測合金的室溫力學性能，采用透射電鏡(TEM)和高分辨透射電鏡(HRTEM)分析合金的顯微組織。結(jié)果表明：當預變形量為15%時，合金的屈服強度和抗拉強度取得最大值，分別為456.1 MPa和501.6 MPa，繼續(xù)增大預變形量會導致強度下降；而合金的伸長率隨著預變形量的增大而逐漸下降。2519A鋁合金在T9I6工藝中強化方式主要為形變強化和析出強化；合金的形變強化效果隨著預變形量的增大有增大的趨勢，但提升幅度逐漸減小。預變形過程中引入的位錯能夠與合金在預時效階段析出的GP區(qū)相互作用，從而改善位錯分布。當預變形量增大時，基體內(nèi)會發(fā)生回復作用導致位錯密度減少，且后續(xù)時效過程中GP區(qū)析出被抑制，對強化相θ′相的形核產(chǎn)生不利影響，減弱析出強化的效果。
關(guān)鍵字: 2519A鋁合金；斷續(xù)時效；力學性能；顯微組織；預變形
（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
