Micro and sub-micron surface structuring of AZ31 by laser re-melting and dimpling

n this work, the use of ns-pulsed fibre laser for surface structuring of AZ31 Mg alloy is investigated. Surface re-melting was employed to change surface morphology, especially in terms of surface roughness. Dimpling by percussion microdrilling was investigated to control the hole geometry.. With surface remelting mono-directional and homogeneous surfaces were obtained with F-l < 500 J/cm(2). Above 500 J/cm(2) particle generation was observed, which induced sub-micron structure growth with nanofibrous features. Moreover, surface roughness could be controlled below the initial value and much higher. With dimpling, transformation from gentle to strong ablation was observed at F-0=10.3 J/cm(2). XRD analysis was employed to link oxide growth to the surface morphology. Tensile tests were carried out to assess the damage on the mechanical properties after surface structuring. (C) 2015 Elsevier Ltd. All rights reserved.