3D printing of bulk thermoelectric materials: laser powder bed fusion of N-type silicon germanium

International audience ; Among Additive Manufacturing (AM) methods, Laser Powder Bed Fusion (L-PBF), also called Selective Laser Melting (SLM), is prevalent to printing complex metal parts in small and medium series. Recent studies in L-PBF processing develops the manufacturing of new materials, including thermoelectric (TE) materials. This study presents manufacturing of an N type Si$_{80}$Ge$_{20}$ powder by L-PBF. Silicon germanium alloy is a TE material intended for high temperature applications. It is the first time that this semiconductor material is studied by AM technology. Dense samples of various shapes and sizes were produced, and a first process window was identified. Structural analyses have been performed, highlighting good densification. Unfortunately, mechanical cracking occurs in all samples. TE properties were investigated on as built samples, displaying low values (ZT = 0.11 at 600 °C), due to poor electrical conductivity. Overall, these results show that L-PBF of silicon germanium is possible, which could open up its scope of applications.