Deformation behaviors of [110] and [112] oriented Sn single crystals were investigated under different temperatures and strain rates. It is shown that there are some differences between [110] and [112] orientations. [110] oriented sample has the higher strain rate sensitivity exponent m≈0.133, strain hardening exponent n≈0.54, activation energy Q≈35 kJ/mol and deforms through multiple--slip. While [112] oriented sample has the lower strain rate sensitivity exponent m≈0.108, lower strain hardening exponent n≈0.46, activation energy Q≈52 kJ/mol and deforms through cross-slip and twins together. The first activated slip system is {010}<100>in [110] orientation. The critical-resolved shear stress (CRSS) is 3.1 MPa which is depended on temperature. Deformation process is controlled by the cross--slip according to the activation energy and slip observation.

Zr50Cu50 melt was undercooled successfully by using electrostatic levitation. Through combination with a high speed camera, the growth velocity of the ZrCu primary phase in the undercooled melt was measured. It was found that the growth velocity increases almost linearly with undercooling, but is extremely low, at least 2 orders lower than those of the normal metals, Si and Ge.

Mn-Cu alloy coatings with fine shape, low dilute ratio and refined microstructure were fabricated on medium carbon steel substrate by means of laser processing, and then treated by electrochemical etching to selectively dissolve Mn atoms in the coatings. Nanoporous Cu coatings with high specific surface area were finally achieved. The sizes of the pores in the etched coatings are mainly ranging from 30 to 50 nm, and the initial composition of coatings has a great effect on the morphology of the nanoporous Cu coatings.

Adopting the “3D pinpointing approach”, compositional dependence of glass--forming ability (GFA) for Ti-(Cu1-xNix)-Sn (0.20≤x≤0.30, atomic fraction) quaternary alloys was systematically investigated. The alloy with the optimized GFA is located at Ti38Cu37.8Ni16.2Sn8. Its critical diameter for metallic glass formation is near 1.0 mm for the rods fabricated using Cu mold casting. This metallic glass exhibits the supercooled liquid region ΔTx of 56 K and the reduced glass transition temperature Trg of 0.57. By characterizing the microstructure of the arc-melted Ti38Cu37.8Ni16.2Sn8 alloy, it is indicated that solidification of the alloy melt undergoes a pseudo-binary eutectic reaction of L→Ti5Sn3Cu+TiCuNi.

A rectangle crevice assembly was used to measure the change of potential of steel X70, pH value and oxygen content in the crevice with time under the simulated disbonded coating. The effects of cathodic polarization potential, crevice thickness, holiday size on the crevice corrosion behavior of steel X70 in Na2SO4 solution were investigated. It is found that the dissolved oxygen was depleted within the crevice and thus shifted the solution to a more alkaline state. The oxygen depletion has no relation with the applied potential. The potential of the steel reaches the protected potential range, pH value of the solution increases and the protection distance becomes longer when the applied cathodic potential is more negative. Overprotection would result in the hydrogen evolution. The potential drop (IR) of the solution mainly occurs in the vicinity of the opening. The polarization degree decreases the thinner or smaller holiday crevice.

The effect of CO2 on the stress corrosion cracking (SCC) behavior of X70 pipeline steel in simulated Ku'erle soil solution was investigated by polarization curve, EIS and slow strain rate testing (SSRT). The morphologies of fracture surface of X70 pipeline steel in the solution with the different partial pressures of CO2 were analyzed by SEM. The results show that the dissolved CO2 reacted with the corrosion product of FeCO3 and a dissolved complex (Fe(CO3)2 2-) is formed. The cathodic regime representing evolution of hydrogen is also affected by the presence of dissolved CO2. The SCC of X70 pipeline steel in dissolved CO2 solution follows the mechanism of hydrogen-facilitated dissolution. As the increase of the pressure of CO2 in the solution, the effect of hydrogen induced cracking is enhanced.

High-speed metal-active gas (MAG) arc welding experiments were conducted to determine the critical welding speeds at which humping defects occur, the spacing between two adjacent humps along the welding direction, and the cross-section morphologies of the hump and the valley in a humping bead. Based on the weld pool images sensed during high-speed MAG welding process, the forming mechanism of humping bead is analyzed and verified through up-hill and down-hill welding experiments. Meanwhile, the effect of the compositions of shielding gas on the weld bead formation in high--speed MAG welding is also analyzed.

A Ni-Al-Cr3C2 welding wire produced by metal-powder-core technique was pile-up welded on the surface of DZ125 alloy. During welding, the physical heat of arc and Ni-Al exothermic reaction made Ni react with Al to form Ni3Al as matrix, and the precipitated Cr3C2 dissolve again to form fine Cr-rich M3C2 and M7C3 phases distributed in matrix during solidification. The size of chromium carbide particles near the coating/substrate interface is smaller than that near the surface of welding layer due to the difference of cooling rates. In addition, alloying elements in DZ125 alloy diffused into welding melting pool, and then were carbonized or oxidized. The formed carbides and oxides are mainly influenced by the concentration of the alloying elements and the free energies of formation of these compounds. As a result, many carbides and oxides are rich in Ta, Hf, Ti and W. With reaching coating surface, these compounds decrease in amount and even disappeare.

The processes of initial plastic deformation of single crystal Cu in nanoindentation are simulated by using quasicontinuum method. The indenters with three different widths are used and the corresponding curves of load-displacement are analyzed to determine the critical loads of dislocation emission, which are basically in agreement with the loads predicted from energy point of view. The mechanical and microstructural characteristics of dislocation nucleation are revealed by analyzing the displacement field beneath the indenters. The general regularity of the increase of geometrically necessary dislocations beneath the indenter is presented. The motions and annihilations of dislocations in the unloading are discussed qualitatively.

The movement of glide dislocations in Cu/Ni films during nano indentation and friction was simulated by using 3D and 2D molecular dynamics methods respectively, and the interactions between interface and glide dislocations were analyzed. The results show that the repulsive force produced by the misfit dislocation network at the interface prevents the glide dislocations accessing or passing through the interfaces; the image force arising from the modulus difference across an interface confines the glide dislocations to move within Cu individual layer. Both of the above forces can be used to explain the strengthening mechanism of Cu/Ni multilayers.

A new 3D mathematical model describing the electromagnetic stirring (EMS) in the round billet continuous casting mold was developed and the method combining the finite element--finite volume was used to solve the Maxwell's equations and the turbulent Navier-Stokes equations. The characteristics of magnetic field, flow field, temperature field and inclusion trajectory during EMS were analyzed considering the influences of the exciting current intensity and frequency. The simulated magnetic field in the mold is in good agreement with the measured data in the real steel plant, the electromagnetic force is circumferential distribution at the horizontal section of billet. Molten steel forms two pair of recirculation zones in the longitudinal section of the mold and recirculates at the horizontal section. Most of superheated molten steel is stranded in the upper region of mold, the core temperature of billet reduces dramatically and the temperature gradient at the solidifying forefront of billet increases. Most inclusion particles accumulate in the upper zone of mold and do a swirl--like motion. The flow behaviour, temperature distribution and inclusion motion in the mold are all influenced obviously by the exciting current intensity and frequency.

The Ni-based single crystal superalloy was bonded by the transient liquid phase (TLP) bonding using Ni-15Cr-3.5B amorphous ribbon as an insert alloy. The microstructure characteristics in the joint during TLP process were evaluated by OM, SEM and TEM. The electron back scattering diffraction (EBSD) method was applied to determine the crystallographic orientation between the bonded interlayer and substrates. The results indicated that the joint consists of a bond, diffusion and base zones, in the meantime M23B6 +γ and MB+γ eutectics formed in the bond center and the fine M3B2 phases occurred in the diffusion zone. The γ' phases both in the bonded interlayer and in the superalloy substrate are almost identical after homogenization treatment. Due to the epitaxial growth of the isothermal solidification fronts from each mating surface, the crystallographic orientation between the bonded interlayer and the bonded substrate has a good match.

To reveal the deformation regularity of tailor-welded tube (TWT) with dissimilar thickness during hydro-bugling, finite element analysis (FEA), experiment and mechanics analysis were conducted on the deformation behaviors of the thinner tube and the thicker tube, the initiation and expanding of the plastic deformation and the factors which affect bulging harmoniously. The effects of dissimilar thickness on the stress and strain history were analyzed. It is indicated that the deformation of thicker tube lags behind the thinner tube during bulging process. For the thinner tube, the plastic zone first occurs at the middle zone, and then expands towards two ends simultaneously. As for the thicker tube, the plastic zone first occurs at the end adjacent to the weld-seam, and then expands to another end gradually with the pressure increasing. The deformation compatibility can be improved with increasing the hardening exponent n and the length ratioη. No matter what the length ratio, the axial strain is tensile strain for the thinner tube, and compress strain for the thicker tube.

Commercial pure Ti discs were fluorine ion-implanted by plasma immersion ion implantation technique, and the morphology and chemical composition of the modified surface layers were characterized by SEM and XPS, respectively. MG-63 cells were seeded on the surfaces of modified Ti discs in 24-well cell culture plates at a density of 2x10 4 mL-1 and examined by the molecular biology technique for 6, 24 and 48 h. It was confirmed by immunofluorescent staining that the formation of collagen-I on the implanted Ti was significantly more than that on the pure Ti. Furthermore, the reverse transcription polymerase chain reaction and Western blotting showed that the expressions of mRNA and protein of collagen--I on the implanted Ti were fairly greater than those on the pure Ti. It can be concluded that the modified surface containing fluorine is beneficial to improve the biocompatibility of Ti.