Densification and Properties of Bimodal 316L Stainless Steel Produced by Binder Jetting Printing with Addition of B4C

Abstract

Boron-based aids are commonly introduced to tackle the unsatisfactory densification of SS316L parts fabricated by binder jetting (BJ) technology. However, there is scarce study on the effect of sintering aids on the mechanical performance. This work investigates the effect of B4C aids and sintering temperature on the mechanical performance and microscopic morphology of BJ printing SS316L parts. SS316L powders with a bimodal size distribution were adopted to enhance density and reduce the shape distortion. Besides, B4C was added as a sintering aid to promote densification during sintering. The results show that the bimodal powder is in favour of the density increase and the sintering process. The sintering temperature is largely reduced with the addition of B4C. Further, the mechanical performance is mainly affected by the final density and B4C content. In view of a comprehensive evaluation of shape retention and properties, B4C content of 1 wt.% and sintering temperature of 1250°C are expected to be the optimal parameters.