Applied Mechanics and Materials Vol. 470

Abstract: On the basis of a total of 382 ABO₃-type compounds, the structural formability of ABO₃-type perovskite compounds is investigated by using the bond valence model method. A new two-dimensional structural map approach for predicting the formability of ABO₃-type perovskite compounds that relies on the ideal bond distances with the combination of bond valence parameter, coordination number and oxidation state is proposed. The sample points representing compounds of forming perovskite and non-perovskite are distributed in distinctively different regions. Some misclassified compounds are analyzed and some new compounds are tested within the new structure map. The developed approach can be used to search for new perovskite and perovskite-related compounds by screening all possible elemental combinations.

Abstract: The changes in the growth quartz ampoule of AgGaS₂ are studied. Coating a layer of carbon film on the inner surface of growth quartz ampoule is an effective measure to prevent AgGaS₂ melt conglutinate with quartz ampoule. It can prevent the impurities of quartz ampoule diffuse into the AgGaS₂ melt. The anomalous thermal expansion phenomenon of the AgGaS₂ crystal usually makes the growth quartz ampoule broken, and crystal crack. Double-layer quartz ampoule can solve the problem. High-quality and large-size AgGaS₂ single crystal is obtained by using carbon coated and double-layer growth quartz ampoule. These methods are simple and effective.

Abstract: The Tb complex C₆H₁₄O₁₉Tb₂ has been synthesized from a hydrothermal reaction and the crystal structure has been determined by means of single-crystal X-ray diffraction. The Tb atom is coordinated by nine O atoms. The molecular structure stabilized by the O-H…O hydrogen-bonding interactions.

Abstract: The Tb complex C₉H₂₄O₂₁Tb₂ has been synthesized from a hydrothermal reaction and the crystal structure has been determined by means of single-crystal X-ray diffraction. The Tb atom is coordinated by nine O atoms. The molecular structure stabilized by the O-H…O hydrogen-bonding interactions.

Abstract: PFM (phase field method) was employed to study microstructure evolution, and considering the effect of solute concentration to the undercooling, we developed a phase field model for binary alloy on the basis of pure substance model. In the paper, the temperature field and solute field were coupled together in the phase field model to calculate the crystal growth of magnesium alloy in directional solidification. The simulation results showed a non-planar crystal growth of planar to cellular to columnar dendrite, the comparison of different dendrite patterns were carried out in the numerical simulation, and with the increasing of the anisotropy, the second dendrite arms became more developed.

Abstract: A new copper complexe [Cu (Hdmg)₄(teda)]6H₂O(H₂dmg=dimethyl glyoxime;teda=triethylenediamine) was synthesized by solution method of nickel nitrate with corresponding ligands. Single crystal X-ray diffraction analysis reveals that crystal belongs to monoclinic, space group C2/c. The Cu²⁺ is five-coordinated with five N atoms of two dmg molecules and one teda molecule. The pdc anions, as a bridging ligand, link two adjacent Cu ions, forming a dinuclear structure. The structures and properties of complexes have been characterized by elemental analysis and IR spectrum. We also studied the electronic structure and orbital energies of the title complex by DFT methods, and the results reveals that the energy gap between LUMO and HOMO is disappeared. CCDC: 952374

Abstract: It is significant and necessary to carry out the development of self-compensation lubricating composites. In this paper, the current research of self-lubrication composites is summarized. The lubrication mechanism of the high temperature self-compensation lubricating composites is introduced and the research progress of matrix material and lubricant material of the composites is reviewed.

Abstract: Nowadays, pineapple leaf fibre (PALF) is getting more attention in research area since its showed the enhanced properties to be utilized in few industries. From the previous studies, it has been proved that, PALF is mechanically sound as a composites reinforcement agent and its showed the good contribution in pulp and papermaking production. Due to its enhanced properties, PALF now is commercialized as an alternative textile fiber. PALF is silky, fine and textile grade. Apart from being used as an alternative fiber for home textile and apparel, PALF meet the basic requirement to be used as technical fibers. Instead of having a good strength, PALF also have a reasonable length as well as can be pliable. All of these are the main principle of rope making fibers hence make PALF have huge potential to be used as rope making fibers. This paper will present the possibility of converting PALF into textile yarns and then into rope yarns for cordage and rope making. The methodology involved is included PALF extraction, PALF spinning, and PALF twisting. Finally, this paper will present the expected approached for the upcoming work area.

Abstract: The concrete can be taken as a composite material consisting of mortar matrix, aggregates and the bond between them in mesoscopic. And the shape of aggregate is assumed to be sphere and the mortar matrix is supposed to satisfy the D-P yield criteria. The energy density support function is introduced to reflect the yield surface of mortar matrix. In order to solve the non derivability on the yield boundary, the function approaching series is constructed to substitute for the energy density function. Finally, a macro-mesoscopic yield criterion of concrete material is derived by nonlinear homogenized technique. Through this macro-mesoscopic yield criterion, the influence regularity of the bonding status of interface and the fraction of aggregate on the macro friction coefficient is explored. //

Abstract: Because of the differences in application fields, regions, seasons and others, there are great changes in the service temperature. Therefore, it is very important to study the effect of temperature on the tribological behavior and service life of the polymeric composites, which has great significance for the material design and application selection of the modified PTFE three-layer composites. The tested results showed that the friction coefficient of the samples decreases with the increase of the test temperature. The wear loss rises gradually as the temperature increases, except for the abnormal higher wear at 20°C due to the crystal structure transformation of PTFE at l9°C. The wear mechanisms at different temperatures are different: at lower temperatures, the main wear mode is adhesive transfer and fatigue wear and a little peeling, belonging to normal wear. At higher temperatures, the main wear mode is a large number of adhesive transfer with large deformation or even melting.