[T7] AM Sinter Based Technologies

[16A-T7-25] Effect of B Addition on Density and Properties in 316L Stainless Steel Manufactured by Filament-Based Material Extrusion Additive Manufacturing

*C. Suwanpreecha¹, A. Sakkaeo¹, N. Parsompech¹, S. Songkuea¹, A. Manonukul¹ (1.National Metal and Materials Technology Center (MTEC), National Sciences and Technology Development Agency (NSTDA), Thailand)

Keywords:Material extrusion additive manufacturing, Boron, Density

Filament-based material extrusion additive manufacturing (FB-MEX/M) is popular for its simplicity and cost-effectiveness to fabricating metal parts. However, FB-MEX/M parts often have voids and porosity from printing and sintering, which reduce their sintered density and mechanical properties. In conventional powder metallurgy, addition boron (B) to 316L stainless steel improves sintered density through liquid phase formation during sintering. This study investigates the effects of B addition on the relative sintered density, microstructure, mechanical, and tribological properties of 316L alloys fabricated by FB-MEX/M. Three in-house developed 316L filaments were used: B-free, 0.3 and 0.6 wt.% B. After sintering, the relative sintered density increased with B content, reaching 99% (0.6 wt.% B). B addition reduced and altered the pores from irregular to rounded shapes and B-rich phases appeared in the 0.6 wt.% B specimen. Hardness and wear performance also improved with B addition.