Understanding the significant effect of boron content on the printability of IN738LC superalloy fabricated using laser powder bed fusion

Abstract

This study intends to investigate the effect of boron on the cracking behavior of Inconel738LC during laser powder bed fusion, which has been rarely reported in previous literature. 2 batches of Inconel738LC powders with different contents of boron are selected to fabricate parts. More cracks are detected in the sample fabricated by the powders with a high content of boron compared to the low-content-boron powders. The formation of boride is confirmed through transmission electron microscope, atom probe tomography and Thermo-Calc calculation, leading to solidification cracking at the final stage of solidification. In addition, the cracks tend to occur at the grain boundaries with high misorientation angles. Significant enhancement in the mechanical performance is achieved with the marked decrease of the boron due to a low level of cracking in the samples.