Аннотации:
Выполнено исследование сплавов Cu–Ag–Sn методами ТПД и статистического моделирования. Представлены результаты ТПД эксперимента
по совместной поверхностной сегрегации атомов Ag и Sn в разбавленных
растворах серебра и олова в меди в поликристаллическом и жидком состояниях. Приведены также данные компьютерного моделирования поверхности этих сплавов методом Монте-Карло в сочетании с методом погруженного атома. The study of Cu–Ag–Sn ternary alloys by the methods of temperature-programmed desorption
(TPD) and statistical modeling is сarried out. The results of the TPD experiment on the combined surface
segregation of Ag and Sn atoms in dilute solutions of silver and tin in copper in polycrystalline and
liquid states are presented. It was found out that the desorption of particles from the surface of the alloy
occurs from regions enriched with this component. In addition, the silver atoms form, in the main,
slightly layered islets. Data are also provided for computer simulation of the surface of these alloys by
the Monte Carlo method in combination with the embedded atom method (EAM). Using the EAM
method, it was possible to avoid a priori assumptions about the composition and structure of the alloy
surface. Simulation showed that the binding energy of surface atoms is close to the experimental activation
energies of thermal desorption for Cu and Ag atoms. But there is a significant difference for tin atoms.
Secondly, in the modeling for the solid state of the Cu98Ag1Sn1 alloy, the surface concentrations of
ΘAg ≈ ΘSn = 30 at.%, which for Ag atoms are close to the results of the TPD experiment. In the melt, the
degree of surface segregation is reduced to 8 at.% Ag and 14 at.% Sn. Both the TPD experiment and the
simulation give an excess of 10 to 30 times the surface concentrations of Ag and Sn over bulk values,
both in the solid and in the liquid state of the alloy. Third, computer models reveal surface structures in
the form of zigzag chains of Sn atoms, which alternate with chains of Ag atoms. The profiles of tin concentrations
in alloys confirm the hypothesis of a two-layered character of segregation of tin.
Описание:
А.В. Гусев, С.И. Морозов, А.Е. Чудаков,
Южно-Уральский государственный университет, г. Челябинск, Российская Федерация
E-mail: gusevav@susu.ru. A.V. Gusev, S.I. Morozov, A.E. Chudakov
South Ural State University, Chelyabinsk, Russian Federation
E-mail: gusevav@susu.ru