摘要
采用累积叠轧(ARB)工艺制备了1100/7075铝合金层状复合板,并对其进行固溶峰时效热处理。利用扫描电镜(SEM)研究了固溶时效热处理对铝合金复合板微观组织和力学性能的影响,分析了拉伸过程中的PLC(Portevin-Le Chatelier)效应。结果表明:随着复合板层数的增加,界面呈现明显的波形特征,轧制协调变形使7075铝合金层颈缩,1100铝合金层弯曲;复合板层数大于40层时,屈服强度基本不变,拉伸强度随层数的增加而增加;随着复合板层数的增加,界面分层逐渐取代韧窝成为主要的断裂机制,这有利于复合板韧性的提高;固溶时效处理后复合板中MgZn2第二相粒子分布更加弥散均匀,应变硬化速率提升,均匀伸长率大幅度提高;第二相粒子引起的晶格畸变使Cu、Mg溶质原子在析出相周围的偏聚,溶质原子对位错的反复钉扎和脱钉,导致PLC效应的产生。
1100/7075 aluminum alloy laminated composites were prepared by accumulative roll bonding(ARB) process, and solid solution and peak aging treatment were performed. The effect of solid solution and aging heat treatment on microstructure and mechanical properties of the aluminum alloy laminated composites was studied by scanning electron microscopy(SEM), and the Portevin-Le Chatelier(PLC) effect during tensile process was analyzed. The results show that with the increase of the number of layers, the interface of the laminated composites shows obvious waveform characteristics, the coordinated deformation of rolling makes the 7075 aluminum alloy layer necking and 1100 aluminum alloy layer bending. When the number of layers is more than 40 layers, the yield strength of the laminated composites is basically unchanged, and the tensile strength increases with the increase of the number of layers. With the increase of the number of layers, the interfacial stratification gradually replaces dimples as the main fracture mechanism of the laminated composites, which is beneficial to the improvement of toughness of the laminated composites. After solid solution and aging treatment, the distribution of MgZn2 second phase particles in the laminated composites is more uniform, and the strain hardening rate increases, the uniform elongation increases greatly. The lattice distortion caused by the second phase particles results in the segregation of Cu,Mg solute atoms around the precipitated phase, and the repeated pinning and de-pinning of solute atoms to dislocations, which leads to the PLC effect.
作者
陈泽军
莫太骞
陈全忠
刘庆
CHEN Ze-jun;MO Tai-qian;CHEN Quan-zhong;LIU Qing(College of Materials Science and Engineering,Chongqing University,Chongqing 400044,China;State Key Laboratory of Mechanical Transmission,Chongqing University,Chongqing 400044,China;WISDRI Engineering&Research Incorporation Limited Company,Wuhan 430223,China)
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2019年第12期59-67,共9页
Transactions of Materials and Heat Treatment
基金
国家自然科学基金(51421001)
中央高校基本科研业务费(2019CDQYCL001,2019CDCGCL204)
关键词
层状复合材料
累积叠轧
时效处理
界面
PLC效应
laminated composites
accumulative roll bonding
aging treatment
interface
PLC effect
