The electrical resistivity of liquid Bi-Ga alloys has been measured in both heating and cooling process using the four-probe method. Anomalous behaviours of resistivity with temperature appear in heating process and are irreversible in subsequent cooling process. Microheterogeneity is then proved to exist in the melt during heating and depicted by the emulsion model. The evolution of heterogeneity in liquid Bi 33?3 Ga 66?7 alloy was investigated through both isothermal and non-isothermal experiments. The results indicate that Bi 33?3 Ga 66?7 melt experiences a polydisperse-monodisperse-homogeneous state transformation upon successive heating above critical temperature.

Magnesium alloys have been widely applied in many fields, because of their high strength-to-weight ratio. However, magnesium alloys have high chemical activity and are easily corroded. The poor corrosion resistance of magnesium alloys greatly limits its further application. In this paper, the zinc phosphate conversion coatings were prepared on the surface of AZ91D magnesium alloys. Nano-zinc oxide was the source of zinc and the zinc phosphate conversion coatings were prepared by the given process: 1.25 g/L NaNO3, 3 g/L C6H8O7 H2O, 2.5 g/L NaF, 5.5 g/L ZnO, 12.5 mL/L H3PO4, reaction temperature 50°C, reaction for 30 minutes. The full immersion uniform corrosion test was conducted for the fabricated coatings. The morphology and composition of corrosion in different corrosion stages were characterized by XRD, SEM and other microscopies. The results showed that: (1) the corrosion process of the conversion coatings could be divided into three stages: the dissolution of the conversion coatings, the corrosion of the matrix and the deposition of insoluble matter; (2) XRD analysis and other methods found that the pine-needle magnesium oxychloride compounds were formed in the process of immersion firstly, and it was dissolved into Mg(OH)2 over time; (3) With the extension of immersion time, Mg(OH)2 increased continuously and played a major role in corrosion prevention. The deposited Mg(OH)2 was divided into two layers. In the initial deposition stage, it was mainly evenly dispersed on the surface of the alloy to form a tightly arranged inner layer. Afterwards, the crystals of Mg(OH)2 agglomerated and formed a sphere, becoming the outer layers.

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The computer simulation of the structural evolutions of Al nanowires on cooling has been carried out based on the embedded atom method potential. The infinite Al nanowire was modeled by super-cell with a one-dimensionally periodical boundary condition along the [001] direction. The simulation results indicate that the microstructure of Al nanowires changed from amorphous to helical multi-shelled structure along with the drops of cooling rate. The helical multi-shelled structure possesses some features of amorphous structure, but it is more stable than the later. Moreover, the Al nanowires still keep the helical multi-shelled structure even if the cooling rate decreased to 1010 K/s.

Series of AZ91 alloy samples are prepared by adding different levels of Mg-Zn-Y quasicrystal master alloy under normal casting condition. The microstructure and mechanical properties of these samples are investigated by using of XRD, SEM, EDS and tensile test. It is shown that morphology of β- Mg17Al12 phase changes from continuous nets to discontinuous nets or even to particles. As results of these changes, the mechanical properties of AZ91 alloys are significantly improved until the addition level passes 6%.