Al Alloy And Mg Alloy's Performance Influenced By Surface Nano-Technology

Surface nano-technology is a kind of surface treatment in material processing technology, which can make the materials' surface have excellent performance of the nano-materials, and the treated materials can remain the anti-creep property of the coarse grained material. In recent years, surface technology has been the concern of academics, and the surface technology has created a new path for nano-materials used in daily life.In this paper, we focus on the change of mechanical and electrochemical properties taken by high-energy shot peening on the surface of Al and Mg alloy. After the shot peening, we can find that the grains on the most surface are so fine that it can't be distinguished. However, as the grains far away from the surface, the grains get bigger, and the surface hardness and stress decreased gradually, the electrochemical changes as the the size of grain increased at the same time.We use micro-hardness analysis, X-ray diffraction, optical microscope and scanning electron microscopy analysis, EDX analysis and anode polarization methods to study the performance of shot-peening Al and Mg alloy, and received the following conclusions:About the grain refinement and mechanical properties, we can find that the grains on the surface are so fine that the grains can not be distinguished, but with the distance to surface increased, the grain can be gradually distinguished, which means that the grain get bigger. Form the XRD analysis, it can be calculated that the grain in the most surface of Al alloy is around 109 nm, and it is about 68 nm in Mg alloy's surface. From OM and SEM photos, we can roughly estimated that Mg alloy's treated surface is about 200μm, and Al alloy's treated surface is about 120μm, which is according with the result of micro-hardness experiment.In addition, through the research on Mg alloy's grain grown up and the peak migration in different thermal environment, we can known that Mg alloy's nano-structure can stand within the 200℃, when the temperature go to rise, Grain appears to be crystallization of grown up, and lattice distortion situation has improved significantly, nano-surface failed at the same time.About the electrochemical properties, we can found the shot peening Al and Mg alloy's anode potential have increased, and the corrosion current correspondingly decreased, which indicating that shot peening Al and Mg alloy's Corrosion resistance have increased. Through the EDX of the shot peening Al alloy's surface, we find that it have a better corrosion resistance than before, and it has a strong protective effect to the matrix. Although the anti-corrosion properties of shot peening Mg alloy has been upgraded, but there is no fundamental change, and it still can not provide an effective protection to the matrix.