热电材料 Cu₂Se 的选区激光熔化制备及其组织性能研究

The main problem of selective laser melting (SLM) additive preparation of thermoelectric material Cu₂Se is that Se element is easy to burn under the action of high energy density heat source of laser. At present, there is no commercially available Cu₂Se powder for 3D printing, and no scholars have used SLM to prepare medium temperature thermoelectric material Cu₂Se. In this study, laser-induced high-temperature self-propagating reaction and ball milling method was used to prepare Cu₂Se powder with good fluidity for SLM additive manufacturing. Under the optimized process parameters, Cu₂Se thermoelectric material additive parts with smooth surface, good mechanical properties and excellent thermoelectric properties were obtained. Results show that the grain growth of Cu₂Se bulks prepared by SLM has obvious anisotropy in the horizontal and vertical directions. The grains in the vertical section are mainly slender columnar crystals with a length of about hundreds of microns growing along the deposition direction, and the horizontal section is an equiaxed crystal with a size of about tens of microns. There are nano-scale micropore defects at the grain boundaries on the horizontal section. The ZT values measured in the vertical and horizontal directions at 673 K are 0.75 and 0.33, respectively. The maximum compressive strength along the vertical and horizontal directions is 125.08 and 42.69 MPa, respectively. The average microhardness (HV) of the additive parts is 628.4 MPa. The thermoelectric properties of Cu₂Se prepared in this study are comparable to those of Cu₂Se prepared by traditional methods in the vertical direction, and the mechanical properties are good, indicating that it is feasible to prepare Cu₂Se thermoelectric materials by SLM. This study provides a new way for the preparation of medium temperature thermoelectric materials.