(1. 湖南科技大学 机电工程学院，湘潭 411201；
2. 湖南科技大学 高功效轻合金构件成形技术及耐损伤性能评价湖南省工程研究中心，湘潭 411201；
3. 江麓机电集团有限公司，湘潭 411100)
摘 要: 采用扫描电镜、透射电镜、室温拉伸测试及疲劳性能测试等方法，研究T87和T9I6断续时效处理对51 mm厚2519A铝合金厚板厚向组织与性能的影响。结果表明：经T9I6断续时效处理后，2519A铝合金晶粒组织和析出相沿厚度方向分布不均匀。从表层到中间层，随着晶粒长径比的增加，粗大第二相和未固溶相体积分数也随之变大，时效析出相的体积分数随之降低；与T87态合金相比，2519A-T9I6合金晶内析出相的体积分数更大，且分布更均匀，其厚向屈服强度与抗拉强度较T87态分别提高50 MPa和90 MPa。同时，由于预时效处理后的中间层相对较软，故冷轧变形能够深入中间层，在加工硬化以及析出强化的共同作用下，T9I6合金厚向硬度整体提高，硬度不均匀性降低。在相同疲劳加载条件下，T9I6态厚向的疲劳寿命更高，疲劳极限较T87态提高了21 MPa。
关键字: 2519A铝合金厚板；断续时效；微观组织；力学性能
（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
