Influence of laser surface remelting on al-si alloy properties

Abstract

The paper treats Al-Si alloy after laser surface remelting by the changes in microstructure and micro-hardness of a modified surface layer. Laser remelting of the thin surface layer was carried out with different energy inputs into the as-cast specimen surface. The remelting conditions were varied by application of different laser beam pulse duration. After solidification of surface remelted layer a fine-grained microstructure is formed. Such a microstructure increases micro-hardness of Al-Si alloy by about 60 to 80%. The variation and size of mainly tensile residual stresses in surface remelted layer greatly depends on the cooling rates i.e. laser pulse duration. Precipitation annealing after the process of laser surface remelting additionally influences the reduction of residual stresses. © 2012 Journal of Mechanical Engineering.