高能球磨制备Al-5%Pb纳米复合结构中第二相Pb的长大行为  

Growth behavior of secondary phase Pb in Al-5%Pb nano-composite structure prepared by high energy ball milling

作　　者：吴志方[1] 张磊[1] 吴江[1] 刘超[1] WU Zhifang ZHANG Lei WU Jiang LIU Chao(Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081, China)

机构地区：[1]武汉科技大学钢铁冶金及资源利用省部共建教育部重点实验室,武汉430081

出　　处：《粉末冶金材料科学与工程》2017年第3期349-353,共5页Materials Science and Engineering of Powder Metallurgy

基　　金：国家自然科学基金资助项目(51201118)

摘　　要：采用高能球磨法制备Pb质量分数为5%的纳米Al-5%Pb复合粉末,经过单轴向冷压成形后,于573~723K温度范围内在氩气保护下进行不同时间的等温退火处理,利用X射线衍射仪、扫描电镜和透射电镜等分析与观察复合粉末的物相组成与显微形貌,研究弥散分布在纳米晶Al基体上的纳米相Pb的长大行为。结果表明,尽管组成相Al和Pb的尺寸均在纳米级,Al-5%Pb复合结构中第二相Pb的长大仍遵循传统两相体系中第二相的长大规律,即纳米相Pb尺寸的三次方与退火时间呈线性关系。但纳米相Pb的长大激活能接近基体相Al的晶界自扩散激活能,其长大是通过Pb原子沿Al基体的晶界扩散实现的。The high energy ball milling was used to prepare A1-5%Pb nano-composite powders with Pb mass fraction of 5%, and then, the bulk alloy was obtained by a combination of uniaxially cold pressing and isothermal annealing at 573-723 K for different times under the protection of pure argon gas. The phase composition and microstructure of composite powders as well as the growth behavior of dispersed nanophase Pb embedded in nanocrystalline Al matrix were investigated by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. The results show that the growth of secondary phase Pb in Al-5%Pb nano-composite follows the coarsening law of secondary phase in conventional grain sized composite alloys. The cube of the average particle radius ofPb nanophase grows proportional with the annealing time even though the size of the constituent phase Al and Pb is in nanometer range. The activation energy for coarsening of Pb nanophase is close to that of grain boundary self-diffusion of matrix phase Al, and the coarsening of Pb nanophase is controlled by the diffusion of Pb atoms along the grain boundaries of the Al matrix.

关 键 词：高能球磨 AL-PB合金 纳米复合结构 第二相 长大 

分 类 号：TB383[一般工业技术—材料科学与工程]