Maximizing vitrification and density of a Zr-based glass-forming alloy processed by laser powder bed fusion

Abstract

Owing to the layer-by-layer processing, laser powder-bed fusion (LPBF) allows to overcome the size limitation imposed by the high cooling rates necessary for the synthesis of bulk metallic glasses (BMGs). The fabrication of amorphous and highly dense parts via LPBF is however very challenging, since the processing parameters affect both requirements in a contrasting manner. Here, a large number of specimens is fabricated from the glass-forming Zr52.5Cu17.9Ni14.6Al10Ti5 alloy by LPBF at varying processing conditions. Processing maps of amorphicity and density are provided and evaluated concerning porosity, structural relaxation and crystallization. Optimum processing conditions for maximized density and amorphicity are identified. The present dataset is designed to quantify the correlation between relative density, amorphicity, volumetric energy density and normalized enthalpy criteria. Pearson and Spearman correlation analyses show an equally strong dependence between both criteria and the relative density and an inverse moderate dependence with amorphicity. Based on the results, a modified enthalpy criterion is deduced. It correlates strongest with density amongst the non-dimensional parameters.