Identification of a Ni0.5(Al0.5-xMnx) B2 phase at the heterophase interfaces of Cu-rich precipitates in an α-Fe matrix

A phase with the stoichiometry Ni(0.5)(Al(0.5-x)Mn(x)) is observed at heterophase interfaces of Cu-rich precipitates in an alpha-Fe matrix, utilizing atom-probe tomography. First-principles calculations are utilized to determine the substitutional energies, yielding E(Mn -> Ni)=0.916 eV atom(-1) and E(Mn -> Al)=-0.016 eV atom(-1) indicating that the manganese atoms prefer substituting at Al sublattice sites instead of Ni sites. A synchrotron radiation experiment demonstrates that the identified phase possesses the B2 structure. (C) 2007 American Institute of Physics.