Laser-beam powder bed fusion prepared polycrystalline Fe-Ga-Sn alloys: microstructure manipulation, modulus softening, and magnetostriction improvement

Magnetostrictive Fe-Ga alloys are a new generation of smart materials with broad applications. However, polycrystalline Fe-Ga alloys always face limitations in magnetostriction performance due to microstructural complexity. In this work, laser-beam powder bed fusion (LPBF) was utilized to fabricate Sn-doped polycrystalline Fe 81 Ga 19 alloys, aiming to enhance the magnetostriction performance via microstructure manipulation. Results indicated that LPBF extended the solid solubility of Sn in Fe 81 Ga 19 alloys owing to high cooling rate. The extended solid solubility resulted in more Sn atom substitution that induced both 9-fold increase in the relative content of Modified-D0 3 (M-D0 3 ) nanoinclusions embedded in A2 matrix and 31% softening in the elastic modulus along [001] direction. Moreover, the LPBF process, benefiting from the features of non-equilibrium solidification and remelting, was conducive to preserving the disordered M-D0 3 phases and suppressing the formation of ordered phases. Consequently, compared with LPBF-prepared (LPBF-ed) Fe 81 Ga 19 alloys, the LPBF-ed (Fe 81 Ga 19 ) 99 Sn 1 alloys exhibited simultaneous magnetostriction improvement by 54% and decline in switching field intensity by 32%, which was attributed to the synergistical effects from disordered phases and modulus softening. Meanwhile, the LPBF-ed (Fe 81 Ga 19 ) 99 Sn 1 alloys exhibited favorable cytocompatibility and accelerated corrosion due to Sn 4+ hydrolysis and micro-galvanic formation. These findings indicated that the LPBF-ed (Fe 81 Ga 19 ) 99 Sn 1 alloys might be potential magnetostrictive alternatives in smart devices.