Stability of the Metastable Phases in the Co-Ta System Studied by ab initio and Thermodynamic Calculations Together with Ion-Beam-Mixing Experiment(Condensed Matter : Structure, Mechanical and Thermal Properties)

概要

論文の詳細を見る
Employing ab initio calculations, the relative stabilities of the possible crystalline structures at compositions of CoTa_3, Co_3Ta and CoTa were predicted and based on thermodynamic calculations, the possible structural phase transitions were predicted over a broad composition range for the metastable crystalline Co-Ta alloys. To confirm the relevance of the calculations, ion-beam-mixing experiments were conducted using Co-Ta multilayered films with various overall compositions. It turned out that the experimentally observed formation of metastable crystalline Co-Ta phases agreed reasonably well with the theoretical predictions and that the glass-forming range of the Co-Ta system was determined to be within 25-70 at. % of Ta, matching fairly well with that estimated from thermodynamic calculations. Moreover, a reverse martensitic phase transformation was observed in the CoTa_2 multilayers upon ion irradiation. In addition, steady-sate thermal annealing of the Co-Ta multilayered films also provided some evidence in support to the ab initio and thermodynamic calculations.
社団法人日本物理学会の論文
2005-09-15