不同热处理状态铝合金在电磁成形条件下的成形性研究

目的 研究不同热处理状态下多种铝合金在准静态拉伸和电磁单向拉伸条件下的成形性能,并探究其中机理.方法 选择不同牌号(1060,3003,5052)和不同热处理状态(加工硬化态和完全退火态)的铝合金材料,获得材料在准静态和电磁成形条件下材料的成形性能,并通过扫描电镜(SEM)和透射电镜(TEM)对1060铝合金试样进行显微断口和微观组织分析.采用数值仿真方法,获取板料和线圈的最佳相对位置.结果 与退火态材料相比,在电磁成形条件下加工硬化态材料的成形性能提高得更多,特别是在1060铝合金中,退火态试样准静态拉伸的伸长率和动态拉伸的伸长率几乎一致,而H24态试样的动态拉伸伸长率(20.2％)为准静态拉伸(5.1％)的3.96倍.扫描断口发现电磁成形断裂面更窄,韧窝大小更均匀.1060-O试样电磁成形后,晶粒内部位错密度低,微观结构主要为亚晶.1060-H24试样电磁成形后的组织中位错密度较高,出现位错胞.结论 加工硬化态材料中存在的初始缺陷有利于电磁成形过程中位错的产生和交滑移的发生,从而提高合金成形性.

Formability of Aluminum Alloy with Different Heat Treatment States under Electromagnetic Forming Condition

The purpose of this paper is to study the formability of various aluminum alloys with different heat treatment states under quasi-static tensile and electromagnetic unidirectional tensile conditions, so as to explore its mechanism. Different 1060, 3003 and 5052 aluminum alloy with different heat statement states (work-hardening state and fully annealed state) were selected to obtain the formability of them under quasi-static tensile and electromagnetic forming (EMF) conditions. And the fracture and microstructure of 1060 aluminum alloy samples were analyzed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The optimum relative position between the sheet and the coil was obtained by numerical simulation. The experimental results show that the formability of the work-hardening samples are improved more under EMF condition. Especially in 1060 aluminum alloy, the elongation of the annealed sample under quasi-static tensile condition is almost the same as that under dynamic tensile, while the dynamic tensile elongation (20.2%) of H24-state sample is 3.96 times of that under quasi-static tensile condition(5.1%). It is found that the fracture surface of electromagnetic forming is narrower and the dimple size is more uniform. After EMF, the internal dislocation density of 1060-O sample is low, and the microstructure are mainly subgrains. The dislocation density of 1060-H24 sample is higher and dislocation cells appeared after EMF. The initial defects in work-hardening materials are beneficial to the occurrence of dislocation and cross-slip in EMF, so as to improve the formability of the alloy.