In this paper Cu thin films with different texture components were deposited on Si(111) and Al2O3 substrates by magnetron sputtering technology at room temperature. And the dynamic scaling method was developed to characterize surface roughening of the two films. The result shows that the growth exponent increases when the intensity of Cu (111) orientation increases. A surface roughening mechanism of polycrystalline columnar films growth was proposed to explain this phenomena，in which the influence of grain configuration and grain boundary can be negligible and the texture component is an important factor for surface roughening process.

Directional solidification (DS) of Ti-46Al and Ti-43Al-3Si alloys using a polycrystalline seed material of Ti-43Al-3Si by self-made EMCS experimental apparatus with wide range of velocity has been studied. Successful DS ingots were obtained with fully lamellar microstructure parallel to longitudinal axis when the growth rates increased from 60 to 120mm/h. The ingot grown at 60mm/h exhibited typical lamellar microstructure aligned along the growth direction from the seed crystal up to the end part of ingot. On the contrary, as the growth rate increased, the orientation of lamellar microstructure changed beyond the transition point.

Cu-12wt%Al alloy wires were prepared by vacuum melting and argon-shield vertical continuous unidirectional solidification (OCC) process. Effects of process parameters on the solidification forming were investigated; the microstructure and properties of the wires fabricated by OCC process were analyzed. The results showed that Cu-12wt%Al alloy wires, 6mm in diameter, with smooth surface and single crystal, can be continuously and stably fabricated under melting temperature 1250℃, drawing speed 9mm/min, cooling water volume 900L/h. The Cu-12wt%Al alloy wire with elongation 19.7%, Young’s modulus 167.9GPa and conductivity 22.23%IACS shows an excellent combination property.

In this paper the solute concentration in solid solution and precipitated phase content in alloy are altered by solution treatment at different temperature. The influence on dislocation movement is analyzed by test result, and the micro-mechanism of dynamic strain aging (DSA) is discussed. In the test, when solution treatment temperature reduces stepwise from 500℃, the amplitude of the serrated flow decreases until it reaches minimum at 300℃. And the amplitude increases on the contrary when solution treatment temperature reducing unceasingly to 100℃. When solution treatment temperature is higher than 300℃, solute concentration is the key factor of DSA and its increasing leads to the enhancing of DSA. When solution treatment temperature is lower than 300℃, the intensity of DSA is determined by precipitated phase density and enhances with it increasing.

The behavior exceeding peak-aging strength in the RRA condition of three different aluminum alloys has been studied.The results of hardness and tensile strength test indicate that after presaging at 100℃ or 120℃ and retrogressing at 200℃ for various time and reaging treatment,the hardness and strength of studied alloys are all above the value of presaging condition,some of them even exceed the value of peak aging(T6) condition .And the alloys exhibit a desired combination of strength and elongation after RRA treatment.TEM observation shown that the PFZs formed during retrogressing in short time become narrowed and even disappeared after reaging treatment.In this condition ,the precipiatates in the matrix are maily G.P zones and a few η’precipitates.However, the PFZs formed during retrogressing for a long time can not be narrowed after reaging treatment. In this condition ,the precipiatates in the matrix are coarsen.In T6 condition the precipitates has a uniform distribution with obvious characteristic of PFZs and the volume fraction of η’phase is somewhat increased.Corresponding EDS analysis indicates that the PFZs formed during retrogression are the depletion area of solute atoms.On one hand ,This area can be reduced and even eliminated after short time retrogression and reaging treatment.On the other hand ,this area can not be narrowed when retrogressed for long time and reaged. It is suggested that the behavior exceeding peak-aging strength in the RRA condition ascribes to the narrowing and even disappearing of PFZs formed during retrogression in the process of reaging treatment, which reinforces the grain-broundary, while the precipitates in the matrix of the alloys still keep or even exhibit a more dispersed distribution, and obtain a higher effect of precipitation strengthening.

As a new and important problem in condensed state physics, the discontinuous structural change of liquid with temperature rising is testified by various experimental technologies. However, fractal language has been more and more frequently used to describe some disordered physical systems except liquid alloys. This paper has successfully implemented fractal ideas to observe fractal structures in liquid In-Sn alloy and considers its fractal dimension as a physical quantity sensitive to structure. Moreover, from the fractal viewpoint, the mutation of the fractal dimension has indicated once again that the liquid structure change discontinuously with temperature rising.

Employing a realistic many-body potentials for a series of simple melts, including Ag, Al, Au, Co, Cu, Mg, Ni, Pb, Pd, Pt, Rh, and Si, we examined by the molecular-dynamics simulation the scaling laws of viscosity with different expression of the reduction parameters. Our simulation results give the sound support to early attempts at finding the universal scaling laws proposed by Rosenfeld for transport coefficients in liquid metals. Following Dzugutov, we have also arrived at a universal scaling relationship between the viscosity coefficient and excess entropy. In particular, we find that there exists a link between the scaling law and the Arrhenius law, i.e., the excess entropy scaling law for the viscosity coefficient can be interpreted as a straightforward extension of the Arrhenius law.

The microstructure, tensile and creep properties of Mg-6Al-2Sr and two Mg-6Al-(1-2)Sr-1Ca based alloys have been investigated. The results indicate that the as cast microstructure of Mg-6Al-2Sr alloy consists of the dendritic -Mg and lamellar Al4Sr intermetallics at grain boundaries. Calcium addition to Mg-6Al-2Sr alloy results in the formation of Mg2Ca compound and a Mg-Al-Sr ternary intermediate phase, and the significant improvement of creep properties. The SEM microstructure observations performed on the samples after creep tests reveal that the intermediate phases in the Mg-6Al based alloy alloys with Sr and Ca additions have high thermodynamic stability. Discontinuous precipitation of β-Mg17Al12 occurs in Mg-6Al-2Sr alloy during creep deformation, however, no obvious changes have been observed in the microstructure of the alloys with combined addition of Sr and Ca after creep tests. The die cast sample shows finer microstructure and higher room temperature and high temperature tensile properties while relatively lower creep resistance in comparison with the samples which were cast by water cooled mould.

Instant electric field-induced 90 domain switching, crack initiation and propagation in a poled BaTiO3 single crystal, as well as sustained field-induced indentation crack propagation and 90 domain switching in an unpoled BaTiO3 single crystal have been investigated in situ using optical microscopy. The results show that 90 domain switching is a prerequisite for instant field-induced crack initiation and propagation, but that is no direct relation between the site of crack initiation and propagation and the domain switching zones. Delayed propagation of unloaded indentation crack under sustained field can result in enlargement of the indent ation-induced 90 domain switching zones.

In this paper, the effect of N element on the CO2 corrosion capability of the 2Cr13 stainless steel was researched.The corrosion films of the steels were observed by SEM, and the surface components of the films were analyzed by XPS; the electrochemical impedance spectrum (EIS) of the steels was analyzed by impedance measure system ( PARSTAT 2273), and the corrosion rates of the stainless steels was measured by weight loss method. The obtained results show that the structure of the corrosion film of the 13CrMoTiNbN steel is looser, Cr2O3 is replaced by CrN and Na3CrO4 on the surface of the film, and there is a amount of Fe3O4 and a-FeOOH phases. The impedance value of the 13CrMoTiNbN steel is less than the 13CrMoTiNb steel, and the corrosion rate of the 13CrMoTiNbN steel is more.

The density functional theory with the generalized gradient approximation (GGA) is adopted to study the electronic structure and magnetic properties of V13 cluster and doped V12TM clusters (TM: Sc, Ti, Cr, Mn, Fe, Co, Ni, Y, Zr, Nb, Mo, Tc, Ru, Rh). We obtain the binding energy, electronic structure and magnetism of the clusters. Further more, we analyses the formation of cluster magnetisms and the relationship between magnetic moments and electronic structures of clusters. The results show that V12Fe and V12Ru clusters are the most stable structure being having the closed-shell system with larger binding energies and larger energy gaps between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO). V12Y cluster has a giant moment 11μB. The ground states of most clusters are shown to be magnetic, but their magnetic moments are not striking.

Abstract: This paper focuses on the AZ91D die casting magnesium alloy which is used widely in engineering world and proposes a set of mathematical and physical models of microstructure evolution in the solidification process. Coupled with 3D solute concentration field calculation model, a modified 3D micro-scale cellular automaton (CA) model has been founded to simulate the microstructure evolution of AZ91D die casting magnesium alloy. For multi-grains growth simultaneously, this model successfully revealed the whole evolution process of solute diffusion among the primary grains, solute enrichment and the eutectic transformation. The improved model was applied to simulate the microstructure of different parts of the actual AZ91D die casting and simulation results are in good agreement with the experimental.

Specific non-wetting lines with a definite width of 200 μm were prepared on copper substrates. The dewetting of SnAgCu lead-free liquids on the non-wetting line were observed and recorded in-situ during the reflow of the samples. It was found that the shapes of the solder liquids varied with the height of the printed solder paste. As the height decreasing from 950 μm, the separation length of the liquid along the non-wetting line was elongated gradually. For the solder paste with a height of 350 μm, the liquid sphere cap was completely separated by the non-wetting line. The dependence of the critical height of the solder liquid on the width of non-wetting line was proposed based on interfacial energy minimization. The experimental data was comparable. These results gave a clear hint on the origin of solder bridge.