Chapters authored
Effect of Microstructure on Microhardness and Electrochemical Behavior in Hypereutectic Al-Fe Alloy Processed by Laser Surface Remelting
An analysis was made of microstructure of hypereutectic Al-2.0 wt.% Fe alloy treated by laser surface remelting (LSR), microhardness test, and electrochemical behavior test and their numerical simulation was done. Microstructure was analyzed by optical microscopy, field-emission scanning electron microscopy and Vickers microhardness tests. Results obtained in this study indicate in LSR-treatment occurred rapid heating and followed by rapid cooling, resulting in formation of a thin recast layer with a refined microstructure, with dissolution of precipitates and inclusions and formation of metastable phases, however, an overlapping line on consecutive weld fillets was observed. Furthermore, analysis of Vickers hardness were done in the cross-sectional area of treated sample and on the treated sample surface, therefore, result a greater microhardness of the treated region than untreated substrate. Through the electrochemical impedance spectroscopy (EIS) test, laser surface remelting-treated workpiece exhibit higher polarization resistance than untreated, at 11 times higher and capacitive behavior of material is related to aluminum oxide layer properties, then, microstructure characteristic caused by overlapping ratio and multi-track has a strong effect on electrochemical process.
Part of the book: Aerospace Engineering