Effects of Z-axis lifting height on porosity and microstructure by blue laser directed energy deposition

Abstract

The Z-axis lifting height is significant in layer-by-layer fabrication using laser directed energy deposition (L-DED). In this paper, we have deeply examined the porosity and grain morphologies in the double layers of AlSi10Mg by blue laser directed energy deposition (BL-DED). After the deposition of a single track, the depositional head was raised by a certain Z-axis lifting height and then a second layer was deposited. As the Z-axis lifting height increases, the quantity density of pores in the second layer increases, leading to higher porosity. Especially, the boundary of the overlapping area exhibits the highest porosity, measuring 0.84%. The Z-axis lifting height can be set lower than the height of a single track, while maintaining high dimensional accuracy and surface quality.