摘要
采用光学显微镜、扫描电镜、显微硬度计及电子万能试验机等对不同焊前状态下的喷射沉积7055铝合金搅拌摩擦焊接接头的组织与性能进行了研究。结果表明:热挤压板材的焊接接头硬度由母材区向焊核区逐渐升高,焊核区平均硬度为167 HV20,接头最大抗拉强度为291 MPa,断裂伸长率为4.3%,断裂位置位于母材区;峰时效态板材的焊接接头硬度由母材区向焊核区先降低再升高,母材区平均硬度为200 HV20,焊核区硬度为162 HV20,接头最大抗拉强度达到361 MPa,断裂伸长率为3.8%,断裂位置位于热影响区和热力影响区的分界区域。两种板材的焊核区和热力影响区都表现出剧烈的动态再结晶行为。热挤压态板材和峰时效态板材焊接接头的热影响区分别出现亚微米第二相回溶行为和纳米析出相的粗化行为。两种板材的焊核区和热力影响区的强化效应都包括细晶强化、固溶强化和亚结构强化。热影响区内的晶界粗大第二相不受变形热的影响,其强化机制表现为固溶强化和亚结构强化。
Microstructure and properties of friction stir welded joints of spray formed 7055 aluminum alloy under different pre-welding states were studied using optical microscope,scanning electron microscopy,microhardness tester and electronic universal testing machine.The results show that the hardness of the welded joint of the hot extruded plate gradually increases from the base metal zone(BMZ)to the nugget zone(NZ),with an average hardness of 167 HV20 in the nugget zone(NZ),the maximum tensile strength of the welded joint is 291 MPa,and the elongation is 4.3%,with the fracture location located in the base metal zone.The hardness of the welded joint of the peak aged plate first decreases and then increases from the base metal zone to the nugget zone,the average hardness of the base metal zone is 200 HV20,the hardness of the nugget zone is 162 HV20,the maximum tensile strength of the welded joint reaches 361 MPa,and the elongation is 3.8%.The fracture location is located at the boundary between the heat affected zone(HAZ)and the thermal mechanical affected zone(TMAZ).The nugget zone and thermal mechanical affected zone of both types of plates exhibit a strong dynamic recrystallization behavior.The heat affected zones of the welded joints of hot extruded and peak aged plates exhibit sub-micron second phase dissolution behavior and coarsening behavior of nano precipitated phases,respectively.The strengthening effects of the nugget zone and thermal mechanical affected zone of both types of plates include fine grain strengthening,solid solution strengthening,and substructure strengthening.The coarse second phase at grain boundaries in the heat affected zone is not affected by deformation heat,and its strengthening mechanism is manifested as solid solution strengthening and substructure strengthening.
作者
韩念梅
冯迪
陈家劲
吴彤
张保玲
唐建国
HAN Nian-mei;FENG Di;CHEN Jia-jin;WU Tong;ZHANG Bao-ling;TANG Jian-guo(Department of Precision Manufacturing Engineering,Suzhou Vocational Institute of Industrial Technology,Suzhou 215104,China;School of Materials Science and Engineering,Jiangsu University of Science and Technology,Zhenjiang 212003,China;Jiangsu Haoran Spray Forming Alloy Co Ltd,Zhenjiang 212009,China;School of Materials Science and Engineering,Central South University,Changsha 410083,China;Key Laboratory of Non-ferrous Metal Materials Science and Engineering,Ministry of Education,Changsha 410083,China)
出处
《材料热处理学报》
北大核心
2025年第3期226-238,共13页
Transactions of Materials and Heat Treatment
基金
国家自然科学基金(51474240,51801082)
江苏省高校基础科学研究重大项目(23KJA460012)。
