( 1. 太原理工大学 材料科学与工程学院，太原 030024;
2. 中国科学院 金属研究所，沈阳 110016)
摘 要: 采用高能喷丸技术在1420铝合金上制备出纳米晶结构表层，利用X射线衍射仪、透射电子显微镜及高分辨电子显微镜研究由表层沿厚度方向的结构变化特征，并对硬度沿厚度方向的变化进行分析。结果表明：经过表面高能喷丸处理，样品表面形成了厚度约为20 μm的纳米晶层，平均晶粒尺寸由约20 nm逐渐增加到约100 nm；距表层约20~50 μm为亚微细晶层；表面纳米化的程度与塑性变形量有关；表面纳米化是通过位错滑移的塑性变形方式实现的；与样品的内部相比，表面硬度显著提高。
关键字: 铝合金；高能喷丸；表面纳米化；显微结构；硬度
surface nanocrystallization of aluminum alloy
（ 1. College of Materials Science and Engineering,
Taiyuan University of Technology, Taiyuan 030024, China;
2. Institute of Metal Research, The Chinese Academy of Sciences,
Shenyang 110016, China）
Abstract: A nanostructured surface layer was fabricated on an aluminum alloy 1420 by using a high-energy shot peening (HESP) technique. HESP induced structure alone the depth of the treated sample surface layer was characterized by means of X-ray diffraction,transmission electron microscope and high-resolution electron microscope; and the hardness variation along the depth of the treated sample was examined. Experimental results show that nanostructured surface layer of about 20 μm of thickness is formed after HESP, the average grain size increases from about 20 nm in the surface layer to about 100 nm at a depth of 20 μm. In the region of 20-50μm deep from the surface, there exists submicro-fine grained layer. The degree of the surface crystallization is related to the amount of the plasticity deformation.The surface nanocrystallization can realize by the method of the plastic deformation of dislocation slipping. The hardness of nanostructured surface layer is enhanced significantly after HESP compared with that of the initial sample.
Key words: aluminum alloy; high-energy shot peening; surface nanocrystallization; microstructure; hardness
