工艺参数对7075铝合金板材时效成形性的影响

刘大海,谢永鑫,黎俊初

(南昌航空大学 航空制造工程学院,南昌 330063)



摘要:

为评价7075铝合金板材的可时效成形性并掌握最佳的时效成形工艺参数,基于机械加载时效成形试验工装,开展了时效温度和时间对7075铝合金板材时效成形后构件力学性能和物理性能影响的试验研究.结果表明:7075铝合金板材的时效成形性与工艺参数密切相关,随着时效温度和时间的增大,板材的电导率呈升高趋势,而其拉伸性能则呈降低趋势；且合金的拉伸断裂方式与时效状态有关,过时效初期以沿晶韧窝和穿晶韧窝混合型断裂为主,随着过时效进行主要为韧窝断裂.综合考虑构件时效成形后拉伸性能和电导率等情况,合金最佳时效温度为180 ℃,且保温时间不宜长于16 h.

关键词:  7075铝合金  时效成形  力学性能  拉伸断口  电导率

DOI：10.11951/j.issn.1005-0299.20150310

分类号:TG146.2

基金项目:国家自然科学基金(51375220).



Influence of process parameters on creep age forming formability of 7075 aluminum alloy sheets

LIU Dahai, XIE Yongxin, LI Junchu

(School of Aeronautical Manufacturing Engineering,Nanchang Hangkong University,Nanchang 330063,China)

Abstract:

In order to evaluate the formability of AA7050 aluminium alloy sheets during the creep age forming and to optimize the best creep age forming parameters, series of experimental studies were carried out.The influences of ageing temperature and ageing time were investigated by examining the mechanical and physical properties of samples. The results indicated that the creep age forming formability of 7075 aluminum alloy sheets are greatly affected by the processing parameters. With the increasing of ageing temperature and ageing time, the electrical conductivity tends to increase, while the tensile strength decreases. Furthermore, the alloy fracture mode is associated with ageing conditions. At the early over-aged stage, the material fractured through a mixed mode of transgranular and intergranular fracture, especially the trend of dimple fracture increases under over-aged stages. By evaluating the tensile strength and electrical conductivity of the deformed samples, the best performance was achieved by ageing up to 16 hours at 180 ℃.

Key words:  7075 aluminum alloy  creep age forming  mechanical property  tensile fracture  conductivity