Analytic evaluation of the thermal conductivity at the conditions of the powder bed fusion with electron beam (PBF-EB) additive manufacturing (AM) process

In the additive manufacturing powder bed fusion process with electron beam (PBF-EB) process, the thermal conductivity of the powder bed controls the interaction of the electron beam with the material, the heat transfer during the process, the cooling rate and, consequently, the final component microstructure. This property requires to be optimized, and the desired value is achieved at the present day only with a trial and error approach. This work proposes a numerical method that considers the powder bed's geometrical characteristics, including the neck formation among the powder particles. Examples of model applications are reported, considering the Ti6Al4V alloy processed with the PBF-EB process.