Microstructure characteristics of as-surface nanocrystallized 1420 aluminum alloy by high-energy shot peening
(1. College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China;
2. Institute of Metal Research, Chinese Academy of Sciences,
Shenyang 110016, China)
2. Institute of Metal Research, Chinese Academy of Sciences,
Shenyang 110016, China)
Abstract: A nanostructured surface layer was fabricated on 1420 aluminum alloy by high-energy shot peening. Microstructures were characterized by X-ray diffractometer(XRD), transmission electron microscope(TEM) and high-resolution electron microscope(HRTEM), and microhardness measurement was conducted along the depth from top surface layer to matrix of the sample peened for 30min. The results show that a nanocrystalline layer about 20μm in thickness is formed on the surface of the sample after high-energy shot peening, in which the grain size is changed from about 20nm to 100nm. In the surface layer of 20-50μm in depth, the microstructure consists of submicron grains. The surface nanocrystallization is accomplished by dislocation slip. The microhardness of the top surface nanostructured layer is enhanced obviously after high-energy shot peening(HESP) compared with that of the coarse-grained matrix.
Key words: 1420 alloy; aluminum alloy; high-energy shot peening; surface nanocrystallization; microstructure; microhardness