Effects of circular beam oscillation technique on formability and solidification behaviour of selective laser melted Inconel 718: From single tracks to cuboid samples

The inherent drawbacks of selective laser melting technique including serious micro-pore and element microsegregation problems destroy the mechanical property of the component. To overcome this problem, a new approach, circular beam oscillation, was successfully applied in the SLMed Inconel 718 samples including single tracks, thin walls and cuboid samples. On one hand, circular beam oscillation reduces the micro-pores in molten pools and cuboid samples, increasing the relative density of the cuboid sample to 99.95%. On the other hand, circular beam oscillation suppresses the element microsegregation, reducing the formation of Laves phases in SLMed Inconel 718 samples. Moreover, circular beam oscillation enhances the < 001 > texture of thin walls and the < 101 > texture of cuboid samples. The improvement of formability and microstructure of the SLMed samples with oscillation is closely related to cooling rate, thermal gradient and stirring effect during the solidification process. Therefore, circular beam oscillation shows the possibility to overcome the key bottlenecks of the traditional SLM technology and to realize a further industrial application of SLM technology. (C) 2020 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.