Advanced Materials Research Vols. 261-263

Abstract: Because of the high actuation stress and high recovery strain, NiTi shape-memory alloy (SMA) has been proposed for shape/position control and crack closure in structures for many years. In this paper, we demonstrate the feasibility to use NiTi SMA for not only crack closure, but also shape restoration in a silicon/nanoclay composite beam. Instead of embedding SMA into the beam, we use a piece of external SMA wire so that the expensive NiTi SMA can be reused. In addition, both shape restoration and crack closure can be achieved even when the beam is still in working condition, i.e., with external load applied.

Abstract: This paper investigates the mixing effect in zinc-silica composite electrolyte by particle image velocimetry (PIV) and fractal dimension method. Fifteen groups of orthogonal tests including different rotational speed, electric current and height of paddle are carried out to study the mixing homogeneity using fractal dimension method, it is found that the case with paddle height of 1cm, electric current of 0.25 A and rotational speed of 1000 rpm is better than the others, and at last the distribution of silica in composite coating provides a strong evidence for characterizing the mixing homogeneity.

Abstract: The site preference and thermodynamic properties of UT_xAl_12-x (T = Zr, Nb, Mo and Fe) and their related hydrides are studied based on the pair potentials obtained by the lattice inversion method. The calculated result demonstrates that the stabilizing elements Zr, Nb, or Mo prefer to substitute for Al in 8i sites; and Fe atom preferentially substitutes for Al in the 8f site. The interstitial H atoms only occupy 2b interstitial sites in UT_xAl_12-x. The calculated lattice parameters coincide with the experimental values. In addition, the total and partial phonon densities of states are first evaluated for these compounds.

Abstract: An atomistic study is presented on the phase stability, interatomic distances and lattice parameters of the new actinide intermetallic compounds AFe₂Al₁₀ (A = Th, U). Calculations are based on a series of interatomic pair potentials related to the actinides and transition metals, which are obtained by lattice inversion method. The cohesive energy of AFe₂Al₁₀ with two possible structures of YbFe₂Al₁₀-type and ThMn₁₂-type are calculated and compared with each other. Calculated lattice parameters of AFe₂Al₁₀ are found to agree with reports in the literatures. In particular, the phonon densities of states, vibrational entropy and Debye temperature related to dynamic phenomena are evaluated for the first time.

Abstract: To develop 590MPa grade low yield ratio steel for high-rise buildings, the new generation TMCP based on ultra fast cooling (UFC) technology was proposed. Then effects of UFC final temperature on microstructure and mechanical properties were investigated. The results show that the control of composite phases is important to obtain high strength, low yield ratio and high work hardening exponent. When UFC final temperature is 521°C, 22.5% (volume fraction) M-A phases are distributed in bainite ferrite matrix, and the excellent overall properties can be obtained, i.e., the yield strength is 570MPa, tensile strength 760MPa, yield ratio 0.75 and percentage elongation 22% with the Charpy impact energy 284J at -40°C. All these indexes can meet the requirements of relevant standards.

Abstract: The effects of reaction conditions including Fe²⁺, H₂O₂, oxalic acid, and humic acid dosages were discussed on the Fenton degradation of rhodamine B (RB). The optimal reaction conditions of Fenton reaction were 0.15 mM Fe²⁺, 5 mM H₂O₂, and pH 3.0, and the decolorization rate RB (10 mg/L) reached 97.8% after 30min catalytic degradation. The changes of Fe²⁺ concentrations in Fenton system has been focused on in this work. A relatively low concentration of Fe²⁺ was maintained during reaction process when Fe²⁺ and H₂O₂ were added with high concentration, and thus RB was degraded quickly. The results implicated that Fe²⁺ dosage played a very important role in the degradation of RB, and H₂O₂ dosage didn’t have an apparent influence on the degradation of RB in general. The Fenton degradation of RB could be inhibited in the presence of oxalic acid and humic acid, especially at a high concentration of oxalic acid and humic acid.

Abstract: The corrosion behaviors of ultrapure ferritic stainless steels in simulated urban refuse leachate were investigated by means of different measurement methods including steady-state polarization curves, potentiostatic open-circuit relaxation curves and scanning electronic microscope. The results show that the ultrapure ferritic stainless steel 443, 444 and the austentic stainless steel 304 maintained good passive state after being immersed in the simulated leachate for 720h. The descending order of pitting resistance is 444>443>304. According to the passive film equivalent resistance Rp and the interface capacitance Cd obtained by fitting the potentiostatic open-circuit relaxation curves, the descending order of passive film stability is also 444>443>304.

Abstract: The techno-interface of BF-BOF region is an important stage that connects iron making procedure with steel making procedure in the production line, acting as a connecting link between the preceding and the following procedure. It is also the key region to optimize the iron making and steel making process as a whole. In this paper, based on queuing theory method for BF-BOF region simulation, a static simulation method is presented to realize the simulation of dynamic system, WITNESS is used to simulate the M/M/1 queue model. The number of different transportation ladles has been analyzed to influence the BF-BOF region, the best ladles were obtained in order to improve production rate. The results show that the modeling method can reflect the complex system characteristics of BF-BOF region and provide the advice for system optimization.

Abstract: There were different heat treatments to Cu-Zn-Al shape memory alloy. Cement-based smart lost-circulation control material was prepared by the method of rolling agglomeration. And indoor simulation experiment was carried out. The results show that the heat treatment temperature is 800°C, the quenching medium is the boiling water; the leakage is decreased with the increase of the cotton fiber content. When the cotton fiber content is 4%, the leakage is the minimum; the best volume percent of the lost-circulation control material is 20% in the grout.

Abstract: One potential application of aluminium foam sandwich panels in civil engineering is the cladding system which is employed to protect other structures again impact and blast loadings. Finite element (FE) simulation of these sandwich panels subjected to impact loading was conducted by using a commercial software package, LS-DYNA (version 971). The FE model was verified by experimental results conducted previously. Good agreement was achieved between the FE and experimental results. Parametric study was conducted to investigate the effects of skin thickness, core thickness and boundary conditions on the deformation modes and energy absorption of sandwich panels with aluminum foam core.