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Four different configurations of single-atomic-layer-height disconnections on ( 10 1 ¯ 2 ) twin boundary in magnesium are investigated using molecular dynamics simulations. It is found that a prismatic-basal (PB) single-atomic-layer-height disconnection is more stable than a basal-prismatic (BP) single-atomic-layer-height disconnection when each of them is connected with an I1 stacking fault associated with a stacking sequence change of BA B CB. In contrast, a BP single-atomic-layer-height disconnection is more stable than a PB single-atomic-layer-height disconnection when each of them is connected with an I1 fault associated with a stacking sequence change of AB A CA. A stable BP (or PB) single-atomic-layer-height disconnection can transform to a stable PB (or BP) single-atomic-layer-height disconnection when its step orientation changes with a change in the lying plane of the connected I1 fault.

Self assembled monolayers (SAMs) of 1–tetradecylphosphonic acids (TDPA, CH 3 (CH 2 ) 13 P(O)(OH) 2 ) were formed on the 2024 aluminum alloy surface in TDPA-containing ethanol–water solutions with different water content. The adsorption and corrosion protection properties of the SAMs for 2024 alloy in 0.1 mol/L H 2 SO 4 solution were examined and characterized by potentiodynamic polarization, electrochemical impedance spectrum (EIS), Fourier transformed infrared spectroscopy (FTIR), Auger electron spectra (AES) and atomic force microscopy (AFM). FTIR and AES results show that the TDPA molecules were successfully adsorbed on the 2024 aluminum alloy surface, and the density of the SAMs increased with the increasing water content in the assembly solution. The results of electrochemical studies and corrosion morphologies observed by AFM show that a 4 h modification resulted in maximal inhibition efficiencyand the higher the water content in the assembly solution is, the better the inhibition performance of the SAMs can be achieved. The effect of water content in TDPA solutions on the performance of the SAMs is related to the hydration reaction of the metal surface.

A Mg–6Gd–1Zn–0.6Zr alloy has been mechanically tested in the aged and solution treated conditions. The plate showed negligible yield asymmetry in either the aged condition or the particle free condition. This has been attributed to the weak texture that develops during recrystallisation. It is proposed that a negligible yield asymmetry can be achieved with textures weaker than ∼ 5 times random intensity, and that it is not necessary to have a fully random texture, but simply a texture weak enough for basal slip to dominate the deformation in both tension and compression. The ageing treatment provided little strengthening in tension or compression, and this is because the precipitates do not possess the strongest hardening characteristic of coherent shearable particles, which is internal order.

Die-cast Mg–La, Mg–Ce and Mg–Nd binary alloys varying in composition have been used to investigate creep resistance and its relation to microstructure. The remarkable differences in creep resistance observed in these alloys are shown to be related to different levels of rare earth (RE) solute supersaturated in the α-Mg matrix. The results seem to suggest that strengthening of the α-Mg matrix by solid solution and/or precipitation is more important than grain boundary reinforcement by intermetallic phases for the creep resistance of Mg–RE alloys.

The 18R and 14H long-period stacking ordered structures formed in Mg–Y–Zn alloys are examined systematically using electron diffraction and high-angle annular dark-field scanning transmission electron microscopy. In contrast to that reported in previous studies, the 18R structure is demonstrated to have an ordered base-centred monoclinic lattice, with Y and Zn atoms having an ordered arrangement in the closely packed planes. Furthermore, the composition of 18R is suggested to be Mg 10 Y 1 Zn 1 , instead of the Mg 12 Y 1 Zn 1 composition that is commonly accepted. The 14H structure is also ordered . It has a hexagonal unit cell; the ordered distribution of Y and Zn atoms in the unit cell is similar to that in the 18R and its composition is Mg 12 Y 1 Zn 1 . The 18R unit cell has three ABCA-type building blocks arranged in the same shear direction, while the 14H unit cell has two ABCA-type building blocks arranged in opposite shear directions.

Phase equilibria of the La–Mg–Ni system have been analyzed and a complete thermodynamic description is obtained. The thermodynamic descriptions of the three binary systems are taken from the literature. Most of the binary intermetallic phases, except La2Mg17, LaNi3, and La2Ni7_L, are assumed to have zero solubility in the ternary system. Based on the experimental data, seven stable ternary intermetallic phases were taken into consideration in this system. Among them, two ternary compounds were treated as semi-stoichiometric compounds based on the ternary experimental results. The rest were treated as stoichiometric compounds. The calculated phase equilibria were in agreement with the available experimental data. Moreover, with the help of the optimized parameters, the composition dependencies of glass formation ability in the La–Mg–Ni system were predicted by searching local minima of driving forces for crystallization, and the prediction of glass formation ability agrees with the experimental results.

The planar features in a Mg–8Y–2Zn–0.6Zr (wt.%) alloy solution-treated at 500 °C for 1 h have been examined using conventional transmission electron microscopy and atomic-resolution high-angle annular dark-field scanning transmission electron microscopy. Three types of planar features are detected in the microstructure. The first type, which was previously reported to be an intrinsic stacking fault I1 bounded by a Frank partial dislocation, is shown to be the 14H precipitate phase that is associated with Shockley partial dislocations. The second type is also a precipitate phase that has a single unit cell height and is associated with Shockley partial dislocations. The third type of planar feature comprises small ribbon-like stacking faults. These stacking faults are determined as intrinsic I2 type bounded by two Shockley partial dislocations, which is further confirmed by computer simulation. The stacking fault energy associated with the faults is much smaller than that of pure magnesium.

Ultra high molecular weight polystyrene could be prepared by rare earth catalyst systems. Monte Carlo method simulates the kinetics of high viscous system of styrene bulk polymerization and verifies our coordination polymerization mechanism presumptions. The simulation indicates β-hydrogen elimination and monomer transfer reaction are important in the whole polymerization while the deactivation reaction and cocatalyst transfer reaction are in small possibilities. Polymers containing double bond end are regarded as macro-monomers that can be initiated into active chain. Monte Carlo simulation proves such presumption and calculates the average branch degree of 0.5.