Analytical Modeling of Cooling Rates in PBF-LB/M of Bulk Metallic Glasses

Additive manufacturing through laser powder bed fusion (PBF-LB/M) inheres great potential for the processing of bulk metallic glasses (BMGs). The size-independent high cooling rates during the process benefit the fabrication of large and elaborate amorphous components. Albeit, partial crystallization poses a challenge in additively manufactured BMGs, potentially limiting the resulting mechanical properties. In this matter, the complex thermal history during processing often states a remaining uncertainty. Besides in situ measurements and numerical estimations, analytical models can be used to achieve a deeper understanding of the transient temperature evolution. In this work, an iterative solution to the analytical Rosenthal equation is developed and applied to ZrCuAlNb- and CuTiZrNi-BMGs to predict melt pool dimensions and cooling rates during PBF-LB/M. Therefore, temperature-dependent thermal properties are determined via laser flash measurements. The effective absorptivity of the two materials is measured, and single-line experiments were performed as a validation for the approach.