Additive manufacturing of high-quality NiCu/diamond composites through powder bed fusion

Abstract

Diamond composites exhibit exceptional hardness, chemical stability and thermal conductivity, but poor machinability limits their widespread applications. This work for the first time reported the use of electron beam melting technique for powder bed fusion (PBF) of 3D-structured NiCu/diamond composites, resulting in a high relative density (>95 %) and avoidance of graphitization, thereby offering overall excellent mechanical properties. Detailed analyses of the interactions between electron beams and NiCu/diamonds revealed that adjusting the linear energy density (LED) can control densification and local graphitization behavior. A dimensionless volumetric energy density (DVED) range derived from a semi-quantitative model has been proposed. The optimized values of DVED (4.1＜ED*＜5.1) are useful guideline for producing metal/diamond composites with complex 3D geometries for various engineering applications.