Effect of Temperature and Strain Rate on Dynamic Properties of Low Silicon TRIP Steel

The dynamic tensile test of 0.11C-0.62Si-1.65Mn TRIP steel was carried out at different strain rates and test temperatures. The results show that both temperature and strain rate affect the retained austenite transformation. At high strain rates, the uniform elongation decreases, whereas the total elongation and energy absorption increase. The tensile strength is less strain rate sensitive. With raising test temperature, the tensile strength is reduced and the mechanical properties generally deteriorate, especially at 110℃,However, excellent mechanical properties were obtained at 50℃ and 75℃.

Effects of electromagnetic vibration on the structure and mechanical properties of Al-6%Si alloy during directional solidification

The effects of electromagnetic vibration on the grain refinement in directional solid- ification were investigated. It was found that the electromagnetic vibration applied in the melt not only can refine grains remarkably but also can enhance both tensile strength and ductility values of Al-6%Si alloy. SEM graphs show that coarse dendrite structure was broken up into a somewhat globular structure, and the morphology of eutectic silicon was changed from flaky to fibrous under electromagnetic vibration treatment. The refine mechanism under electromagnetic vibration was discussed.

Computer-aided designing and manufacturing of advanced steels

Suitable optimization and simulation were performed using a powerful software package with a mature database as well as modem measurement facilities, which led to the successful designing and manufacturing of advanced steels. In the course of designing, the composition of a large section of prehardened mold steel for plastics was estimated so as to lower the quantities of oxide inclusions to change the type of carbides and to raise the machinability. The composition and process were adjusted to obtain satisfactory surface quality for the prevailing galvanization in transformation-induced plasticity （TRIP） steel. The refuting process of low-carbon steel was simulated in the light of both Thermo-Calc and Factsage. Thermodynamic and kinetic analyses were always conducted during the test and the procedure.

Electronic Structure and Catalysis on (001) Polar Surface of Cubic Zirconia

The electronic structure of （001） polar surface of cubic zirconia was studied by GGA（WC） approximation. We found the cubic lattice near （001） surface showed an intensive tendency to transfer to tetragonal lattice. The metallic state appeared on both the terminations. For O-termination, some O2p states were vacated and hole carriers concentrated on surface oxygen-ions. For Zr-termination, some Zr4d states became partial occupied for the loss of O2p states. We observed the hole states were mainly localized at the corresponding ions on surface for both the terminations, while the charge states on Zr-termination were dispersed on surface.

Crystalline and Magnetic Enhancement of Nanocrystalline MnZn Ferrites Fabricated under a High Magnetic Field

Nanocrystalline Mn0.6Zn0.4Fe2O4 particles are synthesized under magnetic fields of O and 6 T, and their structural and magnetic properties are investigated. The magnetic field enhances the grain size and the lattice strain. Magnetic measurements show that the majority of the 6 T nanoparticles are superparamagnetic nearly from 40 to 300 K. It is interesting that the saturation magnetization of the 6 T sample is about 18% and 16% higher than that of the 0 T sample at 120 and 300K, respectively.

Solidification structure of eutectic Al-Si alloy under a high magnetic field-aid-electromagnetic vibration

An electromagnetic vibration was generated by simultaneously imposing a strong static magnetic field （up to 10 T） and an alternative electricity current to the metal. Its effects on the solidification structure of eutectic Al-Si alloy have been investigated experimentally. It is found that the eutectic structure has been refined by solely imposing high magnetic field while it is coarsened under the electromagnetic vibration. Furthermore, polyhedral Si grains and non-dendritic α-Al appeared when the electromagnetic vibration strength was strong enough. The refining of eutectic structure is attributed to the decrease of diffusion coefficient caused by the strong magnetic field. The coarseness of eutectic structure may be attributed to the convection caused by electromagnetic vibration. Strong convection may break co-operative growth of eutectic phases to form polyhedral Si grains and non-dendritic α-Al.

In-Situ Alignment of MnBi Crystals Induced by High Magnetic Field above Curie Temperature

Above Curie temperature, MnBi crystals are aligned in situ along the c-axis in a Bi matrix by a high fabrication magnetic field H f of 10 T. Magnetic testing shows a pronounced anisotropy in magnetization in directions normal and parallel to the fabrication field, resulting from the alignment. The successful alignment m v result from the fact that the easy magnetization direction is along the c-axis of MnBi and the high fabrication field of 10 T is large enough to rotate the ）MnBi crystal to this direction even though the temperature is above the Curie temperature.

Fabrication, Structural and Magnetic Properties for Aligned MnBi

MnBi compound is fabricated under a magnetic field of 1 T, and the c-axis of hexagonal MnBi crystal is aligned parallel to the magnetic field direction. The saturation magnetization Ms decreases with the increase of temperature. At temperatures below 20OK, the coercive field Hc is about 150Oe, while the coercive field Hc increases with temperature above 200K. From 200K to 300K, the remnant magnetization Mr and the Mr/Ms increase with the temperature. Below 200K, Mr and Mr/M8 reach roughly a constant value. However, there is an abnormal increase at 100 K in He, Mr and Mr/Ms, which comes from a spin-reorientation in MnBi. Magnetization results show the spin-reorientation for MnBi at about 91 K due to the variations of the anisotropy constants.

Electrochromic-Induced Rechargeable Aqueous Batteries: An Integrated Multifunctional System for Cross-Domain Applications

Multifunctional electrochromic-induced rechargeable aqueous batteries(MERABs) integrate electrochromism and aqueous ion batteries into one platform, which is able to deliver the conversion and storage of photo-thermal-electrochemical sources.Aqueous ion batteries compensate for the drawbacks of slow kinetic reactions and unsatisfied storage capacities of electrochromic devices. On the other hand, electrochromic technology can enable dynamically regulation of solar light and heat radiation. However,MERABs still face several technical issues, including a trade-off between electrochromic and electrochemical performance, low conversion efficiency and poor service life. In this connection, novel device configuration and electrode materials, and an optimized compatibility need to be considered for multidisciplinary applications. In this review,the unique advantages, key challenges and advanced applications are elucidated in a timely and comprehensive manner. Firstly, the prerequisites for effective integration of the working mechanism and device configuration, as well as the choice of electrode materials are examined. Secondly, the latest advances in the applications of MERABs are discussed, including wearable, self-powered, integrated systems and multisystem conversion. Finally, perspectives on the current challenges and future development are outlined, highlighting the giant leap required from laboratory prototypes to large-scale production and eventual commercialization.

Cementite Decomposition in Spherical Graphite Iron by Electropulsing

The influence of electropulsing on cementite decomposition in the spherical graphite iron has been studied. The results indicated that the cementite was decomposed in a short time by high current density electropulsing. With increasing electropulsing time, the in situ nucleation of graphite in cementite was accompanied with the quick decomposition of cementite. The dislocation accumulation adjacent to the cementite and the quick diffusion of carbon atom by electropulsing were main reasons for the quick decomposition of cementite. The in situ nucleation of graphite in the cementite resulted from the dislocation climbing crossing the cementite lamellae.

Three-dimensional knotting of W_(17)O_(47)@PEDOT:PSS nanowires enables high-performance flexible cathode for dual-functional electrochromic and electrochemical device

An efficient integration of electrochromic and electrochemical devices into one flexible entity enables both energy storage and energy-saving dual-functionalities.For this purpose,achieving both high electrochromic and electrochemical performance is the key aspect.Herein,a new 3D architecture is successfully made by knotting W_(17)O_(47)@PEDOT(poly(3,4-ethylenedioxythiophene)):PSS(poly(styrenesulfonate))nanowires with NaWO_(3)nanoknots,and interestingly,the 3D W_(17)O_(47)/(NaWO_(3)-knots)@PEDOT:PSS cathode thus-made simultaneously exhibits a large optical modulation(79.7%at 633 nm),an ultra-long cycling life(76%of original optical modulation retained after 12400 cycles),and a high areal capacitance(55.1 mF cm^(-2)at 0.1 mA cm^(-2)).Our density functional theory(DFT)calculations demonstrate that the much improved dual-functional performance is correlated to the raised electronic conductivity and ion adsorption at the W_(17)O_(47)/(NaWO_(3)nanoknots)interface,together with the ion adsorption of PEDOT:PSS in the 3D-knotted architecture.As a proof-of-concept application,different-sized flexible dual-functional electrochromic/electrochemical devices(FDEDs)were assembled and investigated for various application scenarios,including a smart window(15 cm×10 cm),a wearable wristband(20 cm×2.5 cm),and a smart eyeglass.The smart window made of the FDED enables a large temperature difference of 27.6℃ confirm-tested in model houses,where the energy source also powers three light-emitting diodes(LEDs).The understandings of the key governing principles in the electrodes and dual-functionalities provide a timely foundation for the new generation flexible multifunctional devices.

Formation of Nano High Temperature Alloys of Fe-Sn and Cu-Sn Systems by Mechanical Driving

It is well known that ordinary block materials are composed of ordered components which include long-range ordered crystalline and/or short-range ordered amorphous components so that this kind of materials contains a very small quantity of boundaries, such as grain boundary and interphase boundary.On the contrary,

Modeling of Nucleation and Growth of M_(23)C_6 Carbide in Multi-component Fe-based Alloy

Three-dimensional atom probe （3DAP） technique has been used to study the nucleation and growth of M23C6 carbide in a supersaturated multi-component Fe-based alloy aged at 800℃. 3D images indicate that the radius of M23C6 carbide after ageing for 10 min is about 9 nm. Concentration profiles of alloy elements in the carbide are also obtained. Combined with PANDAT and Thermo-Calc software, attempts to model the early stages of precipitation are present. The calculated particle size and composition of M23C6 carbide is in good agreement with 3DAP data.

Free-standing SnNb_(2)O_(6)@CSN film as flexible anode for high performance sodium-ion batteries

Free-standing electrodes are promising candidates for flexible rechargeable batteries, toward the application of flexible energy storage devices, due to their merits of additive-free, lightweight, and high energy density. Herein, we report a free-standing SnNb_(2)O_(6)@CSN flexible film with SnNb_(2)O_(6) encapsulated in 3D carbon skeleton nanofibers by electrospinning and carbonization processes as flexible anode for sodium-ion batteries(SIBs). The 3D carbon skeleton nanofibers serve as ion/electron transport pathway to improve the electrochemical reaction kinetics and meanwhile alleviate the volume changes of SnNb_(2)O_(6) during charge-discharge processes. The as-constructed half-cell(SnNb_(2)O_(6)@CSN‖Na) exhibits excellent cycling stability of 99.2 m Ah/g at 0.5 A/g after 950 cycles(coulombic efficiency of ~100%) and a high rate performance of 108.6 mAh/g at 10 A/g. In addition, the pouch cell can light up the LEDs at different bending angles(0°, 90°, 180°). This research shows a promising anode material for flexible energy storage electronics.

Effect of chloride on spectrum properties of Pr^3+/Ho^3+ co-doped fluorozirconate glasses

An effective method of improving the luminescent properties of rare earth ions in fluoride glasses were reported.The Pr^3+/Ho^3+co-doped fluorochlorozirconate luminescent glasses were prepared,and the effects of chloride on the spectral properties and structure of the glasses were studied.According to the results,the glass stability is improved,and the luminescence intensity in the visible range is significantly enhanced with the introduction of chloride.By introducing 7.5 mol% BaCl2,the luminescence intensity reaches the maximum and increases by three times,The mechanism of luminescence enhancement is explained by analyzing the correlation between the composition and the structure.The chloride ions disperse outside the glass network before the introduction of 7.5 mol% BaCl2 and increased dispersity of Pr^3+and Ho^3+ions in the fluorozirconate glasses.

Diffusion Coefficient of Calcium Ion in CaO-Al_2O_3-SiO_2 Melts

The Nernst-Einstein equation is used to calculate the diffusion coefficient of calcium ion in the CaO-Al2O3-SiO2 system based on the data of the density and electrical conductivity.It is assumed that all the aluminium ions form tetrahedral structure and merge with chain or ring in the case of molar concentration of CaO higher than Al2O3.And in this case,calcium ion is assumed to be the conclusive charge carrier.A formula between the diffusion coefficient and concentration of calcium ion as well as temperature is deduced,which gives an increasing function relation between the diffusion coefficient and the concentration of calcium ions.

Influence of Soaking Temperature on Microstructure of Multi-pass Compression Deformation for Low Carbon Steels

The influence of soaking temperature on microstructure of high temperature multi-pass compression deformation for two low carbon steels(steel A:wC=0.032%and wMn=0.25%;steel B:wC=0.165%and wMn=0.38%)is studied on the thermal-mechanical simulator in order to rationalize the hot-rolling schedule of low-carbon steel and to promote the low-temperature heating technology.The results show that the microstructures of steel A are almost not affected by reducing soaking temperature,but the acicular ferrite forms in steel B when the soaking temperature is reduced from 1 200 to 1170℃,due to its smaller initial austenite grain size according to recrystallization kinetics theory.

Through-Thickness Texture Gradient in Hot-Rolled 25Mn-2.5Si-2Al TWIP Steel

Texture is one of the important factors affecting sheet metal forming performance.The through-thickness texture gradient during the hot-rolling process of twinning induced plasticity（TWIP）steel sheet was investigated using electron backscatter diffraction and X-ray diffraction.With increasing reduction of the TWIP steel,the fraction of∑1 decreased,whereas the fractions of∑3,∑9,and∑27increased.During 53%reduction,a similar trend could be found from its surface to the center.The gradients of intensities of the fibers decreased with increasing hot-rolling reduction.The intensities of face-centered cubic（fcc）shear textures E and Y were higher in the center than that at the surface for both reductions.During 20% reduction,the intensity of fcc plain strain texture S orientation increased from the center to the surface.