Grain refinement of stainless steel in ultrasound-assisted additive manufacturing

Metals and alloys fabricated by fusion-based additive manufacturing (AM), or 3D printing, undergo complex dynamics of melting solidification, presenting challenges to the effective control grain structure. Herein, we report on use high-intensity ultrasound that controls process solidification during AM 316L stainless steel. We find favours columnar-to-equiaxed transition, promoting formation fine equiaxed grains with random crystallographic texture. Moreover, increases number density from 305 mm-2 2748 despite an associated decrease in cooling rate temperature gradient melt pool AM. Our assessment relationship between size indicates crystallites is enhanced ultrasound. Furthermore, amount constitutional supercooling lowering bulk pool, thus creating environment nucleation, growth, survival grains. This new understanding provides opportunities better exploit structure AM-fabricated metal products.