Under the effect of stresses, the interphase energy may be reduced and probably the carbon atoms may redistribute, e.g., segregate at grain boundaries or other defects, and even the carbide may precipitate, resulting in the increase of the driving force for nucleation, in turn, marked raise of the nucleation rate and acceleration of incubation for bainitic transformation. The kinetics under stress is consistent with the kinetics model of ferrite and pearlite transformations under stress, i.e., the modified Avrami equation. Prior deformation of austenite may at first promote the bainite formation but may lead the occurrence of the mechanical stabilization of austenite at some later stage. The mechanism of the mechanical stabilization of austenite during bainite reaction may not be completely analogous with that during martensitic transformation, and it may only be the result from the hindrance of directional growth of bainite by dislocations formed in deformation, retarding the overall transformation kinetics. Model of the austenite mechanical stabilization is expected to be established.

The simple cubic Ag42In45Ca13 (Pa3, a=2.496 nm), which is the 2/1 crystalline approximant of the Ag42In42Ca16 icosahedral quasicrystal, has been found as the dominant phase in the ternary Ag3In3Ca alloy. Its close structural relation to the Ag42In42Ca16 icosahedral quasicrystal was shown by means of SAED (selected area electron diffraction). The decomposition of the cubic Ag42In45Ca13 after annealing or exposure in air was studied using EDS (energy dispersive X-ray spectroscopy), EELS (electron energy loss spectroscopy) and powder X-ray diffraction. Thin foils of the Ag3In3Ca alloy are easily oxidized in air and the product contains Ca, O and some C. In block samples of the Ag3In3Ca alloy exposed to air for 14 d, the cubic Ag42In45Ca13 gradually decomposes, while the amount of the binary AgIn2 and In4Ag9 phases increases. On the other hand, the Ag42In42Ca16 icosahedral quasicrystal is stable both chemically and structurally under the same conditions.

The phase constitution of a highly dense NiTi alloy prepared by combustion synthesis and treated at high temperature solution and aging was analyzed by X--ray diffraction and transmission electron microscopy (TEM). Two kinds of fine precipitates exist in the alloy besides Ti2Ni. One is the rhombohedral structure Ti11Ni14 (Ti3Ni4}) with a=0.67 nm and alpha=113.85 circ,  which has an orientation relationship with the matrix (B2 structure, a=0.302 nm): ＜111$＞Ti11Ni14∥＜111＞B2, {1－10＞Ti11Ni14∥{123}B2. Another one is an unreported metastable precipitate with a long range ordered structure caused by Ni at the positions of Ti in NiTi phase. Its lattice parameter (a=0.873 nm) is about 3 times of that of NiTi matrix and the molecular formula is Ti13Ni14.

The constraint transformation behavior of 7% strained TiNi alloy was investigated, and the experimental results show that the recovery stress formed at the first constraint transformation thermal cycling is the highest, and then decreases with increasing the constraint transformation thermal cycling number. It is indicated that the recovery strain of deformed TiNi alloy is decreased with increasing the constraint transformation thermal cycling number by forming the internal plastic deformation, which results in the decrease of the recovery stress. The reverse transformation start temperature As' of the deformed TiNi alloy at the first constraint transformation thermal cycling is elevated to a higher temperature, but it nearly returns to the original value of undeformed one at subsequent constraint transformation thermal cycling, and does not change with increasing the constraint transformation thermal cycling number.

The concept of deformation enhanced transformation of ferrite in plain low carbon steel and its characteristics are presented. The systematic work indicates that deformation significantly enhances the ferrite transformation of undercooled austenite in plain low carbon steel. Nucleation is the dominant process of the transformation. Until the completion of the transformation, nucleation is always repeated, especially at the zone in front of the newly formed ferrite grains, which restricts the grain growth and leads to formation of very fine ferrite grains. Three stages of kinetics are clearly shown from the experimental measurement, which correspond to nucleation at grain boundaries, at the zone in front of newly formed ferrite grains and at residual austenite.

The hot deformation behavior and the microstructure evolution of a low carbon steel with different initial grain sizes are investigated by uniaxial hot compression at deformation temperatures of 700 ℃ and 600 ℃ and strain rates of 10 s-1 to 10-3 s-1. The effect of initial grain size and hot deformation parameter Z on dynamic recrystallization of ferrite is approached. The results indicate that under the present deformation conditions, the dynamic recrystallization of ferrite takes place in the low carbon steel. The decrease of initial grain size is not only of benefit to the dynamic recrystallization of ferrite at a certain Z value, but also leads to the increase of the critical values of Z for both the dynamic recrystallization of ferrite and the discontinuous dynamic recrystallization of ferrite. It is suggested that the fine ferrite formed by deformation enhanced transformation is beneficial to the occurrence of dynamic recrystallization of ferrite during hot deformation. Further refinement of the fine ferrite can be realized by the dynamic recrystallization of ferrite under a suitable Z value.

By using carbon extraction replica technology and welding thermal simulation, the second phase particles in parent metal, weld metal and simulated coarse grain heat affected zone (CGHAZ) of Ti-V-Nb microalloyed steel were investigated. Experiment results and analysis show that the particle sizes in the steel are less than 100 nm, and the relative content of Ti in particles increases with increasing particle size. During welding, most of carbonitride particles in welding pool dissolved, the dissolved Ti takes part in deoxidation reaction producing TiO, TiO combined with the other deoxidation or desulfuration products to form large inclusion, dissolved Nb and V did not re-precipitated. TiO and MnAl2O4 formed at the surface of inclusions have cubic coherent relationship. A large quantity of carbonitride particles remained in CGHAZ after welding thermal cycle, the shape of particles changed from irregular shape to cubic one, the mean particle size increased and all of these particles are rich in Ti.

The tensile strengths of the duplex microstructural BT25Y titanium alloys with different contents of Al, W, and Mo have been measured at room and high temperatures. According to Kolachev' formula, the equivalent formulae of yield strength and ultimate tensile strength were derived with the experimental results. The calculated strengths from these equivalent formulae also accord with the experimental values of BT25Y titanium alloys with widmanstatten microstructure at variant temperatures.

Edge dislocation emissions from Mode I, Mode II and mixed-mode crack tips along multiple inclined slip planes are simulated, and plastic zones as well as dislocation--free zones are obtained. It is found that the shape of the Mode II plastic zone is quite different from that obtained based on von Mises yielding criterion and consists of three parts in which the biggest one locates in front of the crack tip. For Mode I crack, however, a similar plastic zone is obtained. Under the same magnitudes of applied stress, the plastic zone of Mode II crack is much larger than that of Mode I crack, and the plastic zone of a mixed--mode crack is mainly affected by the Mode II component. Dislocation--free zones exist around all types of crack tips, which have similar shapes as the corresponding plastic zones.

The damage mechanism of 20SiMn low alloy steel in slurry with different particle sizes was studied using a rotating disk system. The results indicate that the curve of mass loss $vs$ particle size exhibits a clear transition point beyond which the mass loss increases sharply. The SEM images of specimens suffering erosion and cavitation of big particles are obviously different from those of small particles. The damage mechanisms under conditions of small particle and big particle are selective erosion of relative soft ferrite phase and ploughing, respectively. Cavitation adds little effect to slurry erosion under condition of small particles, and obvious effect under condition of big particles.

The role of sodium salicylate in electropolymerization of pyrrole on zincated steel was studied by cyclic voltammetry. The results show that as supporting electrolyte, the sodium salicylate inhibits the zinc dissolution and favours the electropolymerization of pyrrole by passivating the substrate. Consequently, an uniform and compact polypyrrole film may be formed on zincated steel.

The kinetic investigation of hydrazine reduction chemical plating nickel on the surface of hexagonal boron nitride with the average diameter 104 μm particles has been carried out. A model, extension-contraction autocatalysis reaction interface, was created which can demonstrate the curves of deposited nickel with time. Based on the model a kinetic expression for the chemical planting process has been derived, and with the expression the experimental kinetic curves could be fitted, experiments verified the model being suitable. SEM morphologies and EDS analysis of the deposited nickel on the BN surface for different times also supported the model.

The effect of Mn and V on hot corrosion of TiAl in (Na, K)2SO4 melt at 900 ℃ has been investigated. The results show that there is a little effect of Mn on hot-corrosion resistance and the scale structure of TiAl alloy. TiAl and TiAl-Mn alloys have a low hot-corrosion rate because the outer layer of the scale is mainly protective Al2O3. Adding V, however, could change the structure of the scale, and then increased hot corrosion rate of the TiAl and TiAl-Mn alloys by one order of magnitude. For TiAl-V and TiAl-Mn-V alloys, the scale is mainly TiO2, and minor Al2O3 and V2O5. V2O5 can induce cyclic acidic dissolution of Al2O3. As a result, the scale of the TiAl-V and TiAl-Mn-V alloys peeled off locally at the early stage of hot corrosion, and the alloys have a large hot-corrosion rate.

Hot corrosion behaviors of (Al, Mn)3Ti-2V and TiAl in (Na, K)2SO4 melt at 900℃ and in Na2SO4+NaCl melt at 850℃ were studied respectively. The cross-sectional morphologies and profiles of elements in the scale formed on (Al, Mn)3Ti-2V show that (Al, Mn)3Ti-2V has excellent hot corrosion resistance in (Na, K)2SO4 melt. The thin scale consists of an outer protective Al2O3 layer and an inner mixture layer of Al2O3, TiO2 and TiS. When NaCl was added in the Na2SO4 salts, however, the hot corrosion resistance of the (Al, Mn)3Ti-2V becomes very poor. The scale is thicker than that in the absence of NaCl by one hundred times of magnitude at least. The scale consists of three layers: an outer layer consisting of porous MnO plus a little Al2O3+TiO2, a middle layer of porous Al2O3 plus trace amount of TiS, and an inner layer of TiO2+TiS.

The surface morphology of corrosion layer, corrosion products and structure of rust layer for AZ91D magnesium alloy in natural city atmosphere were studied by SEM and XRD. The results show that Mg(OH)2 layer forms at the initial corrosion period, then film thickens and cracks appear with continued corrosion under cyclic wet/dry conditions, in the end these cracks develop to reticulate structure. The water vapour is easily condensed and the corrosives gases, salt particles are easily absorbed in the cracks. Meanwhile, the cracks provide the diffusion paths for oxygen and other corrosion pollutants into matrix, which results in severe local corrosion. The major corrosion products are Mg(OH)2, Al(OH)3, Mg2CO3(OH)2•3H2O and Mg2(OH)3Cl•4H2O, which plays a partial role in protecting the matrix, therefore slowing down the average corrosion rate of magnesium alloy in the latter periods.

Weld heat affected zone (HAZ) microstructures of 22SiMn2TiB ultra-strength steel were thermally simulated by means of Gleeble-1500 machine. Polarization measurement of the quenched zone and tempered zone in 3.5%NaCl solution was conducted respectively with potentionstat/galvanostat Solaron SL1280B. The relation between the microstructure and the HAZ corrosion resistance in 3.5%NaCl solution was established. Carbon and boron diffusions, segregation and iron carbide or boride precipitation are dependent on simulated weld thermal cycle peak temperature θmax and continuous cooling time t8/5, and induce the microstructure transformation. The polarization curves and corrosion potentials of the simulated HAZ with different microstructures in 3.5%NaCl aqueous solution are slightly different; the limit diffusion current of dissolved oxygen in 3.5%NaCl solution decides corrosion current. Weld bond, which undergoes anodic dissolution in couple corroding, needs to be protected carefully.

The corrosion behaviors of zinc in bulk simulated acid solution and under thin electrolyte layer were studied with an occluded cell which can control the thickness of electrolyte layer. In the bulk simulated acid rain solution with pH value 2.4--3.8, the electrochemical impedance spectroscopy of zinc consists of a capacitive loop in high frequency and an inductive loop in low frequency, the control step for corrosion of zinc is charge transfer process. The corrosion rate and corrosion potential of zinc increase with decreasing pH value of solution. When pH of solution was lower (2.4 and 2.7), the hydrogen bubble absorbed on the surface of zinc was formed due to strong hydrogen process, which made more severely corrosion of zinc around bubble than the other surface of zinc, therefore, the circle trace was formed on the surface of zinc. Under thin electrolyte layer, the corrosion process of zinc changed with thinning electrolyte layer, when the thickness of electrolyte was no more than 100 μm, the control step for corrosion of zinc is a mixed process consisted of charge transfer and diffusion, and the cathodic processes are inhibited and the corrosion rate of zinc decreases with decreasing the thickness of electrolyte layer.

Corrosion behaviors of bulk amorphous alloy Cu60Zr30Ti10 and (Cu60Zr30Ti10)99Sn1 and their crystallized forms in 3.5%NaCl solution were studied by potentiodynamic polarization experiments and electrochemical impedance spectroscopy (EIS). The results of potentiodynamic polarization experiment show that the anodic reaction of the amorphous (Cu60Zr30Ti10)99Sn1 has a tendency to passivation, and has lower anodic current density. Moreover, EIS experimental result shows that the amorphous (Cu60Zr30Ti10)99Sn1 alloy has higher charge transfer reaction resistance (Rt) than that of the amorphous Cu60Zr30Ti10. Compared with the amorphous alloys, the crystallized alloys have larger tendency to passivation. EIS results of crystallized alloys show two impedance elements, i.e., high frequency and low frequency capacitive loops. The charge transfer reaction resistances of crystallized alloys are larger than those of amorphous alloys.

The microstructures of the Mg65Cu25Y10 alloy solidified under pressures of 2--5 GPa and ambient pressure have been investigated by X-ray diffraction, differential scanning calorimetry and transmission electron microscopy. Experimental results show that the pressure has a great influence on the phase microstructure during solidification process. High pressure leads to the favorable precipitation of nanoscale Cu2(Y, Mg) phase, which is a metastable phase and transforms to stable Mg2(Cu, Y) phase after annealing. The mechanism for the effect of the pressure on the grain size during solidification process of Mg65Cu25Y10 alloy has been discussed.

The effect of mould materials on the magnetic intensity in ingots was numerically simulated, then the magnetic intensities without ingots were measured, and some experiments were conducted to study these effects. The results show that during low frequency electromagnetic casting the mould with high electrical resistivity such as titanium alloy can greatly reduce eddy loss of mould, thus increase useful power. At the same condition, when the ingot was cast by titanium alloy mould (high electrical resistivity), the microstructures is uniform and fine, the average grain sizes at the border and center of the ingot are 24 μm and 27 μm respectively, but when the ingot was cast by aluminum alloy mould (low electrical resistivity), the microstructures of both the border and center of the ingot are coarse, their average sizes are 38 μm and 45 μm. Furthermore, the mould with higher electrical resistivity can increase the content of solute elements within grains. super-high strength Al alloy,

The structures of diamond-like carbon (DLC) films deposited by vacuum arc evaporation with and without curve arc magnetic filter are studied and compared using Raman shifts. The Raman shifts are deconvolved into D peak and G peak with Gaussian-Lorentzion fitness. The effects of the deposition parameters such as bias voltage and bias current strength of curved magnetic fields on the DLC films structures are discussed. The results show that Ar gas pressure has not obvious effect on the formation of the DLC film; moderate bias current increases the sp3 content; the sp2 cluster can be increased for a too high substrate bias. The magnetic curved filter not only can remove the carbon macroparticles, but also can improve the sp3 content.