Influence of thermal process parameters on the properties of material jetted CuSn8 components

Abstract

The material jetting process (MJT) is a well-known additive manufacturing (AM) process for polymers. In recent years, research has also been conducted on the processing of metals using the MJT process. However, most studies were limited to the processing of metals with comparatively low melting points (< 1000°C), such as tin and aluminum. In order to investigate the processability of Cu-based alloys using the material jetting process, the fabrication of components from a copper–tin–bronze (CuSn8) is investigated in this work. For this purpose, first a suitable system consisting of a print head and heated platform was developed and cuboid test specimens were produced at three different droplet temperatures and three different platform temperatures. This is followed by the optical examination of the component surface and the material structure. In addition, the mechanical properties are characterized by uniaxial tensile tests. The resulting fracture surfaces are analyzed using scanning electron microscope images. With increasing temperature of the platform, an improvement in droplet connectivity can be determined. In addition, an increase in grain size can be observed. Increasing the platform temperature from 650°C to 850°C results in an increase in uniform elongation from 0.5% to 54 %. The ultimate tensile strength increases from 103 MPa to a maximum of 330 MPa for the parameter combination of the highest droplet temperature of 1190°C and the highest platform temperature of 850°C. When fracture surfaces are compared, the lower platform temperatures show areas where the newly deposited droplets have not fused with the substrate droplet, which is the reason for the lower values for elongation and strength. The study shows that the temperature of the deposited droplets has a smaller effect on the mechanical strength of the components than does the temperature of the platform.