Study of the Influence of Main Parameters of the Selective Laser Melting Process on the Porosity of Aluminum Alloy RS-300 Samples

Abstract

To date, the technology of selective laser melting has established itself as a method for manufacturing parts of complex shapes from metals and alloys. Aluminum and its alloys are widely used in aviation, space and other industries. The article presents the study of the influence of the main parameters of the process of selective laser melting on the porosity of samples made of Russian-made aluminum alloy RS-300. Samples were prepared using an SLP-250 setup and a multidirectional strategy for scanning with laser radiation the powder layer. Before the experiments, the granulometric, morphological and chemical analysis of the powder was performed. As a result of the experiments, samples with a density of more than 99.8% were obtained. The porosity of the samples was evaluated using a metrological computer tomograph. Pores of round and irregular shape were observed in the samples. Round pores were mainly formed due to evaporation processes and the presence of hollow powder particles. The formation of irregularly shaped pores is associated with insufficient specific energy of the growth mode, which mainly depends on the distance between scanning lines, scanning speed, and laser radiation power. To assess the microstructure of the samples, polished specimens were prepared, on which two types of microstructure were clearly observed. The first type was a fine microstructure in the center of the melt pool, and the second one was a coarse microstructure at the boundary of the melt pool. The occurrence of irregularly shaped pores can be leveled by selecting optimal growing conditions and strict adherence to the technological process.