Change in electronic structure of Ni-Nb alloys at laser beam amorphization

Methods of electron-positron annihilation (EPA), X-ray and metallographic analyses are used to study Ni60Nb40, Ni75Nb25 and Ni85Nb15 alloys after their annealing, deformation and quenching from the liquid state at laser irradiation. According to EPA the state of conduction electrons and ion skeleton electrons in amorphous and crystalline Ni60Nb40 alloys differs. In crystal alloy affinity of positrons for Ni atoms that is due to negative charge transfer from Nb to Ni atoms in Ni3Nb and NiNb compounds and testifies to appreciable contribution of ion component to interatomic bond. After laser beam amorphization of Ni60Nb40 alloy surface charge redistribution between Ni and Nb atoms, taking place under violation of atomic structure periodicity, that provides for amorphous state stabilization and is favourable as to energy, is observed. Rezults of investigation confirm possibility of using experimentally determined ion skeleton (rm) efficient size as amorphous state stability criterion in Ni-Nb alloys