EXAFS-spectroscopy and thermal neutron diffraction study of the effect of deformation by high pressure torsion on the atomic ordering and magnetic properties of the FeCo alloy

•Neutron diffraction demonstrates a decrease of long-range order in FeCo alloy with increasing HPT.•EXAPS spectroscopy demonstrates the retention of long-range order in the nearest coordination spheres of FeCo.•When exposed to HPT an ultrafine B2 ordered domains appear in the FeCo alloy.•Saturation magnetization of FeCo is determined by the atomic interaction in the nearest coordination spheres. The specific features of B2 atomic ordering and the ordering-dependent structure and magnetic characteristics of the FeCo alloy upon quasi-hydrostatic high-pressure torsion (HPT) in the Bridgman anvils at room and elevated temperatures and subsequent annealing have been studied by thermal neutron diffraction, X-ray diffraction, EXAFS spectroscopy, and magnetometry. An abrupt decrease in the degree of long-range order upon HPT has been revealed by neutron diffraction and EXAFS spectroscopy data exhibiting the formation of an almost ideal B2 ordering of in the nearest coordination spheres of Fe and Co atoms.