Excellent strength-ductility synergy in metastable high entropy alloy by laser powder bed additive manufacturing

Abstract

High entropy alloys (HEAs) have attracted scientific interest due to their good mechanical properties and failure resistance, whereas additive manufacturing (AM) has emerged as a powerful yet flexible processing route for advanced materials. However, limitations inherent in both these fields include HEAs display inferior mechanical properties in as cast condition; and AM demands expansion of printable alloys. A new metastable Fe40Mn20Co20Cr15Si5 (CS-HEA) HEA showing stabilized ε-h.c.p. dominated microstructure after laser powder bed fusion additive manufacturing has been evaluated. As-printed CS-HEA showed higher strength due to high work hardenability, whereas substantial uniform ductility is associated with a combination of transformation and twinning induced plasticity during deformation. Additionally, very low volume percent of voids (∼0.1 %) along with high strength-ductility shows excellent printability of the CS-HEA using laser-based additive manufacturing.