Advanced Materials Research Vol. 266

Abstract: Ti45Zr30Ni25RE3 (Y, La) alloys were prepared by melt-spun at wheel velocities of 20 m s–1. Ti45Zr30Ni25 and Ti45Zr30Ni25La3 were composed of I-phase, amorphous and Laves phases. Ti45Zr30Ni25Y3 consisted of amorphous phase and I-phase. The addition of La and Y caused the decrease of maximum discharge capacity and the increase of cycling stability, which should be ascribed to the change of various phase abundant. The high-rate dischargeability of Ti45Zr30Ni25 alloy electrode was better than that of Ti45Zr30Ni25Y3 and Ti45Zr30Ni25La3 alloy electrode, which was attributed to the better electrochemical kinetics.

Abstract: In this paper, microstructure of AL-Cu eutectic alloy is simulated by improving Nestler’s multiphase-field model. The exact physical parameters are used in multiphase-field model, and obtained the steady calculational results. In this numerical calculation, AL and AL2Cu are regard as two independent components. The eutectic microstructure is regard as an admixture of single phase α (AL) and single phase θ (AL2Cu). Using the model, steady eutectic layered growth is simulated, and the simulated results agree well with the solidification theory. At the same time, the stochastic noise is introduced, and eutectic free layered growth microstructure is simulated. The microstructure of primary dendritic crystal and pseudoeutectic is also simulated by enlarging the calculational interval scale, and obtained a better result.

Abstract: The localized electrochemical characteristics of the anodic metal within a zinc/steel couple immersed in seawater was investigated using an Wire Beam Electrode(WBE) composed of 9 zinc wire sensors together with 112 mild steel ones. The results showed that potential and current density distributions of zinc wires were inhomogeneous; main anodic area transferred from the zinc wires adjacent to steel wires to those farther away from zinc/steel interface gradually; besides, some zinc wires behaved as secondary cathodes. This electrochemical inhomogeneity of zinc might mainly be ascribed to the dissimilar distance between zinc and mild steel wire sensors, and their surface electrochemical state as well.

Abstract: The effects of plastic deformation on the microstructure evolution of grade X100 pipeline were investigated by SEM, TEM and EBSD test. The result shows that quasi-polygon ferrite deforms firstly in the initial stage of plastic strain, and then both acicular ferrite and granular bainite change remarkably with the plastic strain value increase. When the tension stress reaches the tensile strength, micro-cracks nucleate around the inclusion and M/A constitute, expand with the plastic deformation increases, finally cracks connection causes the crack penetration until the expiration. Furthermore, the microscopic orientation concentrates in {111} <112> and {112} <110> direction before the deformation, while crystal orientation in {111} direction enhanced after the deformation.

Abstract: Zirconium ethoxide was synthesized by direct electrochemical reaction of anhydrous ethanol with sacrificial zirconium anode in the presence of tetraethylammonium chlorides (Et4NCl) as a conductive agent. The samples of products were characterized by Fourier transform infrared spectra (FT-IR) and Proton nuclear magnetic resonance spectroscopy (1H-NMR). The experiment results show that direct electrochemical synthesis of zirconium ethoxide has high current efficiency and abundant synthetic product compared with the conventional chemical methods. The behaviors of Zr in Et4NCl ethanol solutions were measured through potentiodynamic polarization, cyclic voltammetry, and potentiostatic current-time transient techniques. Effects of the temperature, scanning rate and the Et4NCl concentration were investigated. The results indicate that the electrochemical dissolution of the metal in anhydrous ethanol is a process of corrosive pitting. The rate of pit nucleation and pit growth increases with increasing of temperature and the Et4NCl concentration.

Abstract: Transformation induced plasticity (TRIP) steels have complex multiphase microstructure composed of ferrite, bainite and retained austenite [1]. These metastable retained austenite can transforms into martensite during plastic deformation, which generates a TRIP effect resulting in excellent combination of high strength and ductility even at high strength level [2-5]. For this reason, the TRIP-aided steel sheets are suitable to fabricate automobile parts, as they can offer excellent formability without sacrifice the strength and safety requirement of the steel sheets. As a result, the development of TRIP-aided steels has been a very important issue in the automobile field.

Abstract: Effects of pre-straining, baking temperature and baking time on bake hardening (BH) behavior of cold-rolled dual phase steel were investigated. The results show that the investigated dual phase steel has clear BH behavior. Increased pre-straining led to the BH value decreased, while increased the baking temperature and prolonged baking holding time can all increase the BH value. The mechanics of bake hardening behavior in dual phase steel were discussed, and the effects of pre-staining on tensile strength after baking were also analyzed.

Abstract: The characteristic crystal model is applied to the study of phase stability and thermodynamics in substitutional bcc-based Nb-Mo alloys. The basic principle and method of alloy thermodynamics which is described by the characteristic crystal model is introduced in detail. The thermodynamic properties of the Nb-Mo system are evaluated to describe the Gibbs energies of various phases including both disordered and ordered phases. The phase diagram of Nb-Mo is assessed and predicted. The results are in good agreement with experiments. An unambiguous tendency toward order with a B2 superstructure in a broad range of alloy composition is predicted.

Abstract: Fluorinated benzaldehydes and diphenyl ketones were synthesized via halogen-exchange fluorination in less polar aprotic solvents in the presence of phase transfer catalyst, with or without the irradiation of microwave. The products were easily obtained with significantly enhanced yield and selectivity with microwave irradiation when compared with conventional heating. The yield of products was in the range of 52.0%~94.2%, and the reaction time can be shortened by more than 90% at most in comparison with common heating. In addition, special microwave effect is obvious when reaction was carried in medium polar aprotic solvents. Therefore, more aprotic solvents can be used in halogen-exchange fluorination under the irradiation of microwave.

Abstract: In this paper, influence of temperature on warm temperature equal channel angular of AZ31 alloy was investigated by using numerical simulation and experimental investigation. The effective stress distribution rules and load-stroke curves viartions were obtained at different temperature. And the distribution of effective strain and the rules of deformation uniformity of three temperatures extrusion processing for round workpiece are obtained. The proper temperatures extrusion processing is acquired through comparing the results of three extrusion routes. The effect of the temperature on the accelerated grain refining during the ECAE operation was discussed in the numerical calculations with a view to the use of the process to bulk AZ31 alloys. On the basis of the simulations, the warm ECAE experiments are carried out. The geometries of finally pressed workpieces of the different temperature pressed samples are in good agreement with finite element analysis results．