Effects of boron on microstructure and mechanical properties of Fe-6.5Â wt.%Si alloy fabricated by directional solidification

► Adding boron can refine grains of the columnar-grained Fe-6.5 wt.%Si alloy. ► Adding boron can decrease the solidification segregation level of silicon. ► Both strength and ductility of the alloy could be improved with boron additions.