Influence of Overlapping Tracks on Microstructure Evolution and Corrosion Behavior in Laser-melt Magnesium Alloy
Guan, Ying Chun
Li, Zhong Li
Zheng, Hong Yu
Date of Issue2013-06-03
School of Mechanical and Aerospace Engineering
Singapore Institute of Manufacturing Technology
Overlapping of laser beam tracks has significant influence on surface quality of laser-treated materials. This paper examines how overlapping tracks affect heat flow, solidification microstructure and electrochemical behavior of laser-melt magnesium alloy. Microstructure evolution of laser-melt surface with different overlapping rates at optimized scanning speed is investigated. Results show that solidification microstructure changes from cellular grains to cellular–dendritic and equiaxed dendritic in the overlapped area when overlapping rate increases. Numerical model suggests that Marangoni convection plays a predominate role in determining the solidification microstructure, and it increases significantly with the overlapping rate. The effect of microstructure in-homogeneities caused by overlapping on electrochemical behavior has also been analyzed.
Materials & Design
© 2013 Elsevier. This is the author created version of a work that has been peer reviewed and accepted for publication by Materials and Design, Elsevier. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [http://dx.doi.org/10.1016/j.matdes.2013.05.075].