Selective laser melting fabricated tungsten with thin-walled structure: role of linear energy density on temperature evolution and manufacturing quality

Thin-walled parts has been extensively used in the field of aerospace, refrigeration and electronic equipment for its characteristics of lightweight, material-saving and compact-structure. Selective laser melting (SLM) technology has been regarded as an effective way to manufacture parts with complex structures due to its high flexibility and efficiency. In this work, tungsten thin-walled parts are manufactured at different laser energy densities, and the finite element modelling of manufacturing process is combined with densification, dimensional accuracy and surface roughness measurement to optimize the SLM process parameters of tungsten thin-walled parts. The results indicated that the transient temperature peak is higher at the top position than at the bottom during the manufacturing process of thin-walled parts, which is also the same in the roughness. With the increase of laser energy input, the temperature of the molten pool is improved, which leads to an increment in the wall thickness. A sample with a maximum relative density of 84.5% was obtained at the optimal energy density about 1000 J/mm and its surface morphology exhibits fewer pores and cracks. The sample prepared at the laser energy input of 800 J/m exhibits the superior property of microhardness with the value of 504.3HV_0.2. All these results are significant in the manufacture of thin-walled parts with high performances.