工程科学学报.第42卷.第5期：620-627.2020年5月 Chinese Journal of Engineering,Vol.42,No.5:620-627,May 2020 https://doi.org/10.13374/j.issn2095-9389.2019.05.25.002;http://cje.ustb.edu.cn 热轧7075/AZ31B复合板的显微组织及结合性能 吴宗河，祁梓宸，许朋朋，赵云鹏，肖宏区 燕山大学国家冷轧板带装备及工艺工程技术研究中心.秦皇岛066004 通信作者，E-mail:xhh@ysu.edu.cn 摘要为了研究热轧铝/镁复合板结合强度的变化规律，本文综合考虑压下率、轧制温度和轧制速度等多种轧制参数，单道 次热轧制备了7075A/AZ31BMg复合板.结果表明：在复合板轧制过程中由于热和强变形作用组织发生了动态再结晶，且增 大轧制速度有助于镁基体产生完全动态再结晶.在相同轧制温度下，铝镁复合板结合强度均随压下率增加先升高后降低：强 度升高是由于界面元素扩散宽度的增大和镁合金近界面晶粒组织的细化所致，强度降低是由于大变形导致镁基体近界面处 产生裂缝，以及塑性功产生热量过多使得镁基体温度升高导致的镁侧晶粒长大所致.对复合板进行拉剪实验，铝镁结合界面 剪切强度较低时，断裂发生在复合界面处且成脆性断裂特征，强度较高时断口形貌呈韧性断裂特征，断裂发生在镁基体侧 关键词7075铝合金；AZ31B镁合金：热轧：结合强度：微观组织 分类号TG142.71 Microstructure and bonding properties of hot-rolled 7075/AZ31B clad sheets WU Zong-he,QI Zi-chen.XU Peng-peng,ZHAO Yun-peng,XIAO Hong National Engineering Research Center for Equipment and Technology of Cold Strip Rolling,Yanshan University,Qinhuangdao 066004,China Corresponding author,E-mail:xhh @ysu.edu.cn ABSTRACT Magnesium/aluminum(Mg/Al)bimetallic laminated composites have attracted considerable attention because of their excellent properties.Mg alloys are lightweight structural metals with low density and excellent properties such as high stiffness-to- weight ratio,high strength-to-weight ratio,and good damping capacity.Thus,Mg alloys have considerable potential in automotive and aerospace fields.However,the application of Mg and its alloys is still restricted because of their low corrosion resistance.By contrast,as structural materials,Al alloys are widely used in mechanical and aerospace fields because of their excellent properties,such as light weight,high corrosion resistance,low cost,and good plastic formability.Therefore,Mg/Al laminated composites that combine the advantages of substrates to achieve appropriate coordination,have attracted worldwide attention.To analyze the variation of the bonding strength of hot-rolled Al/Mg clad sheets,various rolling parameters,such as reduction ratio,rolling temperature,and rolling speed,were comprehensively considered in this work.Moreover,7075 Al/AZ31B Mg composite plates were prepared by single-pass hot rolling. Results show that dynamic recrystallization occurs in the microstructure of the Mg matrix during the rolling process because of heat and strong deformation.Furthermore,the increase in the rolling speed contributed to the complete dynamic recrystallization.At the same rolling temperature,the bonding strength of the Al/Mg composite plates first increased and then decreased with the increase in the reduction ratio.The bonding strength increased because of the increase in the element diffusion width across the interface and the grain refinement near the Mg interface.The bonding strength decreased because cracks occurred near the interface of the Mg matrix due to the strong deformation and excess heat generated by the plastic work,resulting in the growth of the Mg side grains with the increase in the temperature of the Mg matrix.The shear test was conducted on the composite plates.When the shear strength of the Al/Mg composite plates was low,shear fracture occurred at the interface with brittle fracture feature.Although the fracture morphology presented a ductile 收稿日期：2019-05-25 基金项目：国家自然科学基金资助项目(51474190)热轧 7075/AZ31B 复合板的显微组织及结合性能 吴宗河，祁梓宸，许朋朋，赵云鹏，肖    宏苣 燕山大学国家冷轧板带装备及工艺工程技术研究中心，秦皇岛 066004 苣通信作者，E-mail：xhh@ysu.edu.cn 摘    要    为了研究热轧铝/镁复合板结合强度的变化规律，本文综合考虑压下率、轧制温度和轧制速度等多种轧制参数，单道 次热轧制备了 7075 Al/AZ31B Mg 复合板. 结果表明：在复合板轧制过程中由于热和强变形作用组织发生了动态再结晶，且增 大轧制速度有助于镁基体产生完全动态再结晶. 在相同轧制温度下，铝镁复合板结合强度均随压下率增加先升高后降低；强 度升高是由于界面元素扩散宽度的增大和镁合金近界面晶粒组织的细化所致，强度降低是由于大变形导致镁基体近界面处 产生裂缝，以及塑性功产生热量过多使得镁基体温度升高导致的镁侧晶粒长大所致. 对复合板进行拉剪实验，铝镁结合界面 剪切强度较低时，断裂发生在复合界面处且成脆性断裂特征，强度较高时断口形貌呈韧性断裂特征，断裂发生在镁基体侧. 关键词    7075 铝合金；AZ31B 镁合金；热轧；结合强度；微观组织 分类号    TG142.71 Microstructure and bonding properties of hot-rolled 7075/AZ31B clad sheets WU Zong-he，QI Zi-chen，XU Peng-peng，ZHAO Yun-peng，XIAO Hong苣 National Engineering Research Center for Equipment and Technology of Cold Strip Rolling, Yanshan University, Qinhuangdao 066004, China 苣 Corresponding author, E-mail: xhh@ysu.edu.cn ABSTRACT    Magnesium/aluminum  (Mg/Al)  bimetallic  laminated  composites  have  attracted  considerable  attention  because  of  their excellent  properties.  Mg  alloys  are  lightweight  structural  metals  with  low  density  and  excellent  properties  such  as  high  stiffness-to￾weight ratio, high strength-to-weight ratio, and good damping capacity. Thus, Mg alloys have considerable potential in automotive and aerospace fields. However, the application of Mg and its alloys is still restricted because of their low corrosion resistance. By contrast, as structural materials, Al alloys are widely used in mechanical and aerospace fields because of their excellent properties, such as light weight,  high  corrosion  resistance,  low  cost,  and  good  plastic  formability.  Therefore,  Mg/Al  laminated  composites  that  combine  the advantages of substrates to achieve appropriate coordination, have attracted worldwide attention. To analyze the variation of the bonding strength of hot-rolled Al/Mg clad sheets, various rolling parameters, such as reduction ratio, rolling temperature, and rolling speed, were comprehensively considered in this work. Moreover, 7075 Al/AZ31B Mg composite plates were prepared by single-pass hot rolling. Results show that dynamic recrystallization occurs in the microstructure of the Mg matrix during the rolling process because of heat and strong deformation. Furthermore, the increase in the rolling speed contributed to the complete dynamic recrystallization. At the same rolling  temperature,  the  bonding  strength  of  the  Al/Mg  composite  plates  first  increased  and  then  decreased  with  the  increase  in  the reduction ratio. The bonding strength increased because of the increase in the element diffusion width across the interface and the grain refinement near the Mg interface. The bonding strength decreased because cracks occurred near the interface of the Mg matrix due to the strong deformation and excess heat generated by the plastic work, resulting in the growth of the Mg side grains with the increase in the temperature of the Mg matrix. The shear test was conducted on the composite plates. When the shear strength of the Al/Mg composite plates was low, shear fracture occurred at the interface with brittle fracture feature. Although the fracture morphology presented a ductile 收稿日期: 2019−05−25 基金项目: 国家自然科学基金资助项目 (51474190) 工程科学学报，第 42 卷，第 5 期：620−627，2020 年 5 月 Chinese Journal of Engineering, Vol. 42, No. 5: 620−627, May 2020 https://doi.org/10.13374/j.issn2095-9389.2019.05.25.002; http://cje.ustb.edu.cn