(1. 湖南科技大學(xué) 機(jī)電工程學(xué)院，湘潭 411201；
2. 湖南科技大學(xué) 高功效輕合金構(gòu)件成形技術(shù)及耐損傷性能評價(jià)湖南省工程研究中心，湘潭 411201；
3. 江麓機(jī)電集團(tuán)有限公司，湘潭 411100)
摘 要: 采用掃描電鏡、透射電鏡、室溫拉伸測試及疲勞性能測試等方法，研究T87和T9I6斷續(xù)時(shí)效處理對51 mm厚2519A鋁合金厚板厚向組織與性能的影響。結(jié)果表明：經(jīng)T9I6斷續(xù)時(shí)效處理后，2519A鋁合金晶粒組織和析出相沿厚度方向分布不均勻。從表層到中間層，隨著晶粒長徑比的增加，粗大第二相和未固溶相體積分?jǐn)?shù)也隨之變大，時(shí)效析出相的體積分?jǐn)?shù)隨之降低；與T87態(tài)合金相比，2519A-T9I6合金晶內(nèi)析出相的體積分?jǐn)?shù)更大，且分布更均勻，其厚向屈服強(qiáng)度與抗拉強(qiáng)度較T87態(tài)分別提高50 MPa和90 MPa。同時(shí)，由于預(yù)時(shí)效處理后的中間層相對較軟，故冷軋變形能夠深入中間層，在加工硬化以及析出強(qiáng)化的共同作用下，T9I6合金厚向硬度整體提高，硬度不均勻性降低。在相同疲勞加載條件下，T9I6態(tài)厚向的疲勞壽命更高，疲勞極限較T87態(tài)提高了21 MPa。
關(guān)鍵字: 2519A鋁合金厚板；斷續(xù)時(shí)效；微觀組織；力學(xué)性能
（1. School of Mechanical and Electrical Engineering, Hunan University of Science and Technology, Xiangtan 411201, China;
2. Evaluation of Forming Technology and Damage Resistance of High Efficiency Light Alloy Components, Hunan Engineering Research Center, Hunan University of Science and Technology, Xiangtan 411201, China;
3. Jiang Lu Electromechanical Group Co., Ltd., Xiangtan 411100, China）
Abstract:The effects of T87 and T9I6 interrupted aging treatment on the microstructure and properties of 51 mm thick 2519A aluminum alloy plate through-thickness were studied by means of scanning electron microscope, transmission electron microscope, tensile test at room temperature and fatigue property test. The results show that, after T9I6 interrupted aging treatment, the grain structure and precipitates of 2519A aluminum alloy are inhomogeneous along the thickness direction. From the surface layer to the middle layer, the grain aspect ratio increases, the volume fraction of coarse secondary phase and undissolved phase increases, and the volume fraction of precipitates decreases. Compared with T87 alloy, the volume fraction of precipitates in 2519A-T9I6 alloy is larger and the distribution is more uniform, and the yield strength and tensile strength of 2519A-T9I6 alloy are increased by 50 MPa and 90 MPa, respectively. As the middle layer is relatively soft after pre-aging treatment, so the cold rolling deformation can penetrate into the middle layer, and the overall hardness of T9I6 alloy through-thickness is improved and the hardness unevenness is reduced under the joint action of work hardening and precipitation strengthening. Besides, under the same fatigue loading condition, the fatigue life of T9I6 state through thickness is higher, and the fatigue limitation has increased by 21 MPa compared with that of T87 state.
Key words: 2519A aluminum alloy thick plate; interrupted aging; microstructure; mechanical property
