Disorder-order transformation in Fe-50 %Co fabricated via laser powder bed fusion

•Laser powder bed fusion suppresses the brittle B2 phase by retaining the metastable BCC A2 phase in the equiatomic Fe-Co alloy.•The suppression of the ordered B2 phase can make these alloys processable in near net shape forms.•Neutron diffraction shows that ordering occurs via classical nucleation and growth when the disordered as-fabricated material is heated.•During cooling, post heat-treatment, ordering occurs via a combination of homogeneous ordering and classical nucleation and growth.