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The grain refinement mechanism of Al–Ti–C grain refiners used in the casting procedure of aluminum has been studied by first‐principles calculation. Considering the controversy over Al3Ti, TiC, or Al3Ti–TiC as nucleation sites, the adsorption behavior of possible nucleation surfaces for Al atoms, including adsorption energies and adsorption sites, as well as the interfacial properties of Al/Al3Ti/TiC are calculated and compared. In the results, it is shown that the Al3Ti(112) surface has a stronger adsorption capacity for Al than TiC. By using the edge‐to‐edge matching crystallographic model and the calculation of the adsorption energy, it is found that the monolayer Al3Ti(112) can be stabilized on the TiC(100) surface, and the combination of TiC and monolayer Al3Ti can significantly improve the adsorption capacity of Al. Interfacial electronic structure analysis shows stronger chemical bonding between Al and Ti at the Al/Al3Ti/TiC interface compared to Al/Al3Ti, which explains that the monolayer Al3Ti covering the TiC surface has the strongest adsorption capacity for Al atoms. Therefore, it is speculated that TiC with a monolayer of Al3Ti covering the surface will serve as a potential nucleation site during grain refinement, which will provide a theoretical reference for future research work. [ABSTRACT FROM AUTHOR]

The effects of pressure on structural stability, anisotropic elasticities and electronic properties of η -MgZn 2 phase were systematically investigated. The smooth variations of lattice parameters a / a 0 , c / c 0 and formation enthalpy Δ H with increasing pressure suggest no structure transition occurred within the studied pressure range, and the decreasing value of Δ H indicate the better thermodynamical stability at high pressure. It is found the elastic moduli are enhanced by increasing pressure, and the large values of both B / G and Poisson's ratio indicate the ductility of η phase. Besides, the elastic anisotropies that result from the distinct atomic arrangements along different orientations are pronounced when applied to compression. Moreover, as the pressure increases, not only the chemical bonds in η exhibit stronger covalency and ionicity, but also the bonding strength in different directions increase to vary extents. This can explain the higher stability and significant elastic anisotropies of η phase at high pressure. • Effects of pressure on stability, elasticties and electronic structure of η-MgZn 2 were investigated. • MgZn 2 that has not undergo structure transition within 0-50 GPa process better thermodynamical stability under high pressure. • MgZn 2 exhibits enhanced ductility and strong elastic anisotropy on (10 1 _ 0) plane when pressure is increased. • The increased pressure leads to greater covalent and ionic bonding characters in MgZn 2. [ABSTRACT FROM AUTHOR]

• The results show that the most stable interface exhibited the largest fracture energy of 2.324 J/m2 and largest tensile stress of 15.302 GPa. • The calculations for the fully relaxed stretching model show that Al exhibited better elongation. • Electronic structure indicates that a uniform distribution of electrons at the interface helped stabilize the interface and improve the interfacial strength. • For L12-Al3Sc||Al interface, the most stable interface contained fewer high-energy-state electrons and more low-energy-state electrons and exhibited the most uniform electron distribution. Deeply investigating the characteristics of the L1 2 -Al 3 Sc||Al interface is a good strategy for improving the ductility and strength of next-generation Al alloys. Herein, rigid and fully relaxed models of L1 2 -Al 3 Sc||Al were studied through first-principles calculations work to reveal the interface strength and fracture behavior. Results show that the most stable interface exhibited the largest fracture energy of 2.324 J/m2 and the largest tensile stress of 15.302 GPa. The calculations for the fully relaxed stretching model show that Al exhibited better elongation. The analysis of the electronic structure indicates that a uniform distribution of electrons at the interface stabilizes the interface structure and improve the interfacial strength. The calculations on density of states reveal that considerable hybridization occurs among the interfacial Al 3s, Al 3p and Sc 3d orbitals, forming s–p–d hybrid orbits. The most stable interface contained low-energy-state electrons than high-energy-state electrons and exhibited the most uniform electron distribution, which are the key factors leading to interface stabilization and strengthening. [ABSTRACT FROM AUTHOR]