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The interaction between a solute and vacancy is crucial for the diffusion and precipitation of alloy elements and ultimately affects the creep resistance and safety of refractory molybdenum (Mo) alloys. In this work, the first-principles calculations of the interaction between solutes (5 light impurity atoms and 23 transition metal elements) and vacancies show that Mo is sensitive to all the light impurity elements, which indicates that these solutes are easy to combine with an Mo alloy and have relatively strong interaction. In most cases, the interaction between the 23 transition metal solutes and vacancy is attractive, but the interaction between solutes V, Ti, and the first-nearest vacancy is repulsive, and the interaction between the early elements in the 3d, 4d, and 5d series and the second-nearest vacancy is also repulsive. Then, we discuss the main factors that affect the solute–vacancy interaction, that is, the effects of electron and strain-elimination. Finally, a solute–vacancy interaction database based on the above effects is established, which would contribute to the research on heat- and radiation-resistant Mo alloys. [ABSTRACT FROM AUTHOR]

The crystalline mechanism of the Pt50Au50 alloy with grain boundary (GB) segregation during the rapid solidification process is investigated using molecular dynamics simulations. The cluster evolution and phase transformation processes during the GB segregation are analyzed by means of the energy temperature (E–T) curve, the pair distribution function (g(r)) curves, common neighborhood analysis (CNA), cluster-type index method (CTIM) and three-dimensional visualizing analyses. It is found that the GB segregation phenomenon of the Pt50Au50 alloy comes from various solidification temperatures of Pt- and Au-centered clusters. Four critical temperatures T1 (1153 K), T2 (1073 K), T3 (853 K) and T4 (753 K) are discovered during the liquid–solid transition, corresponding to the supercooled liquid, Pt-centered atom nucleation, Pt-centered cluster growth, Au-centered atom nucleation and grain growth process, respectively, which is observably different to the solidification process of other alloys. The Pt atoms begin to gather together in the high-temperature liquid before the liquid–solid transition. It is also found that the CTIM proposed by us would provide an effective tool to investigate the GB segregation process. [ABSTRACT FROM AUTHOR]

The plasma parameters like electron temperature (Te) and electron density (ne) on the deposition rate in turn thickness of titanium thin film at different axial and radial positions were studied quantitatively in a DC magnetron sputtering unit. The electron flux (EF) and the electron energy distribution function (EEDF) methods were used to calculate Te and ne using the data collected from multi Langmuir probe setup. The electron density distribution was obtained through the particle-in-cell–Monte Carlo collisions (PI-C‒MCC) simulation method and from IV graph using a Langmuir probe. It was observed that both Te and ne decreased with the increase in axial and radial distances from the cathode centre. The deposition rate of titanium thin films was found to follow the same pattern as Te and ne. The influence of the magnetic field configuration and change of the plasma parameters on the deposition rate were analyzed in the light of simulated and experimental results obtained. [ABSTRACT FROM AUTHOR]