Saibei Wang

First-Principles Study on Solution Strengthening Effect of Cu and Zn in Ag Alloy

A first-principles plane-wave pseudopotential method based on the density functional theory was used to investigate the mechanical properties and electronic properties of AgCu and AgZn solid solution. The VCA models have been set up for solid solution, and elastic constants, bulk modulus and shear modulus, Young modulus and density of states of Cu or Zn doped Ag system were also analysed. The results show that Cu and Zn in Ag alloy play a role of solution strengthening, the solid solution strengthening effect was obviously improved by adding a small amount of Cu(less than 2at.%) or Zn(less than 1at.%). The total DOS of AgCu(Zn) Solid solution is mainly constituted by the Ag 4d and Cu(Zn) 4d states. The AgZn Solid solution has a more stable structure than AgCu solid solution.

An Overview of Phase Diagram and Thermodynamic Parameters of Pt–Au–Sn System

Rare and precious metals materials with unique physical and chemical properties are widely used in aviation, aerospace, navigation, electronic, electric, petroleum chemical industry, glass fiber, waste gas purification, metallurgical and other industries, which are known as “the vitamin of modern industry”. In this article, the development and application of Pt–Au–Sn system, the binary and ternary alloy phase diagrams in the Pt–Au–Sn system, and the related thermodynamic parameters, including phase structure and formation enthalpy of alloy, the cohesive energy and the Gibbs free energy of Pt–Au–Sn system were reviewed, at the same time, the further research interests and the experimental verification of phase diagram of Pt–Au–Sn system were also discussed, which could provide necessary theoretical support for the alloy composition design and industrial applications in the future.

Observation on molten bridge of AgNi10 electrical contact material under different current

The electrical contact-high speed imaging experimental system was developed to investigate the molten bridge phenomena of AgNi10 electrical contact material. The dimension of molten bridge was measured along with measurement of SEM morphology under the load of DC 12 V (8 A to 20 A). A part of the observed results was presented, which showed us some new phenomena. Molten bridge and arc could exist simultaneously. The molten bridge was seen like cylindrical shape, the diameter of molten bridge increased with the increase of current while the length is not sensitive to the change of current.

The foundation and study of a new type of lattice inversion potential for Iridium

In this paper, the lattice cohesive curve of iridium is investigated through first-principles calculations. The double-exponential function to fit the curve is presented. The inversion pair potential curve is generated through Chen’s inversion method. The accurate pair potential function is obtained through fitting by the new double-exponential function. The phonon spectra are calculated using the inversion potential data, the embedded atom method (EAM) potential theory and first-principles method, respectively, to verify the reliability of the inversion potential. The method combining Boltzmann statistics equation with accuracy fitting of lattice cohesive energy curve is proposed to calculate the thermal expansion coefficient. In addition, the bulk modulus and Gruneisen constant in the room temperature are calculated. The results are in good agreement with experiment results, which imply that the inversion potential is effective and accurate.