Papers by Keyword: Crystal Orientation

Abstract: One-axis-oriented Pb (Zr,Ti)O₃ (PZT) films were fabricated using a chemical solution deposition technique on (111)Pt/TiO₂/(100)Si and Inconel625 substrates buffered by nanosheet Ca₂Nb₃O₁₀ (ns-CN). The (001)-oriented PZT crystals (Zr/Ti=0.40:0.60, tetragonal) were preferentially grown on (001)ns-CN/Inconel625, whereas the PZT crystals deposited on (001)ns-CN/(111)Pt/ TiO₂/(100)Si exhibited preferential PZT(100) orientation. The resulting PZT film on (001)ns-CN/Inconel625 indicated remanent polarization of approximately 59 μC/cm², which was significantly larger than that on (001)ns-CN/(111)Pt/TiO₂/(100)Si.

Abstract: This paper describes the fabrication and measurement results of piezoelectric energy harvester arrays based on aluminum nitride (AlN) as a piezoelectric material. The AlN piezoelectric thin film with crystal orientation (002) and crystal orientation (101) is deposited respectively by pulsed_DC sputtering on the different bottom electrode materials. Based on the AlN thin film, the piezoelectric vibration energy harvester arrays with 5 cantilever beams were developed. Then the load characteristics, frequency characteristics, harvester connected in series and parallel properties of harvester were investigated. In addition, we compare the properties of piezoelectric vibration energy harvester arrays with crystal orientation (101) and (002), where a record max power output of 0.23 μW and 0.38μW are obtained respectively when the value of acceleration was 1 g, while for the latter, the maximum power is 9.13 μW at the acceleration of 5.0g with the optimized resistance of 15 kΩ.

Abstract: The effect of overheating treatment on the crystal orientation of the Tb0.27Dy0.73Fe1.9 alloy was investigated. The results indicated that different overheating treatment conditions could obtain different crystal orientation. It means that overheating treatment affects the process of Tb0.27Dy0.73Fe1.9 solidification. The conjectural discussions of these results are also presented.

Abstract: The lamellar crystal orientation and crystal instable growth in polymer ultrathin films were studied. The orientation of lamellar crystal transforms from edge-on to flat-on with decreasing film thickness due to the enhancement of restriction effect of polymer-substrate on the edge-on lamellar crystals. Lamellar crystals in ultrathin films have a instable growth and become a dendrite at the growth front because of the diffusion-controlled growth.

Abstract: The effects of diffusion temperature and time on the mechanism of the surface layers formation during low activity vapour phase aluminizing process on a Ni-base superalloy CMSX4 single crystal was experimentally investigated. The coating morphology of as aluminized samples grown along the substrate [100] and [110] directions of the substrate crystal was analysed by means of SEM, EDS and EBSD techniques. The presence of three layers, where β-NiAl differently combines to γ’, γ and TCP phases, was always observed. The β-NiAl phase in particular displayed two different morphologies and textures depending on the interface movement mechanism generating this phase at its external/internal interface. The presence of secondary precipitated phases within the coating layer, their composition and morphology, helped to understand the coating development process. The surface layer formation mechanism was found to be slightly temperature-dependent.

Abstract: Thin films of MBi₄Ti₄O₁₅ (M = Ca and Sr) with preferential crystal orientation were fabricated using underneath perovskite layers on various substrates. One-axis BLSD films on (100)LaNiO₃/(111)Pt/Ti/(100)Si and epitaxial BLSD films on (100)SrRuO₃//(100)SrTiO₃ were fabricated by chemical solution deposition (CSD). Dielectric constants of the CaBi₄Ti₄O₁₅ and SrBi₄Ti₄O₁₅ films on (100)LaNiO₃/(111)Pt/Ti/(100)Si were approximately 250, while those on (100)SrRuO₃//(100)SrTiO₃ were 220, respectively. The temperature coefficients of capacitance (TCCs) of these films were below 10% in atmospheric temperature range between R.T. and 300°C, which is significantly smaller than those of conventional (Ba,Sr)TiO₃-based capacitors.

Abstract: Freckle occurrence is known to be dependent on the casting size and the superalloy components with large cross section are more prone to freckle formation. In our directional solidification experiment of superalloys freckles are observed in some thin samples, while some significantly thicker samples in the same shell mould cluster remain freckle free. The EBSD analysis shows that the samples with freckles have a good <001> axial orientation, while in freckle free samples the primary dendrite stems diverge from the sample axis. In an analogue system the flow behaviour through a mushy zone was simulated, in which the dendrite network was placed in different orientation. The <001> dendrite array shows the lowest resistance to the vertical melt flow. As the dendrite alignment diverges from <001> orientation, the flow speed slows down and reaches the minimum at the <111> orientation. This orientation effect of the interdendritic permeability explains well why the crystal orientation plays such an important role in the occurrence of freckles in superalloy castings.

Abstract: Thin films of a bismuth layer-structured dielectric oxides (BLSD), SrBi4Ti4O15, with preferential crystal orientation were prepared by means of chemical solution deposition (CSD) technique on (111)Pt/(100)Si substrate with bottom nucleation layers of conductive perovskite oxides, LaNiO3 and SrRuO3. CSD technique was utilized for the film preparation of SrBi4Ti4O15. These films possessed highly crystal orientation of (00l) BLSD planes parallel to the substrate surface. The leakage current densities of the SrBi4Ti4O15 films on (100)SrRuO3//(100)LaNiO3/(111)Pt/Ti/(100)Si and on (100)LaNiO3/(111)Pt/Ti/(100)Si were approximately 10-6 and 10-7 A/cm2 respectively. The dielectric constants of these films in a frequency range of 102 - 106 Hz were from 310 to 350 and 250 to 260 respectively. The value of capacitance change of these films in the range from 20 to 300 oC was about +8 and +5% respectively.

Abstract: The microstructural changes of the primary Al3Ni phases in hypereutectic Al-Ni alloys solidified under various high magnetic field gradients were investigated. It was found that the application of a magnetic field gradient induced an aligned structure of the primary Al3Ni phases similar to those in a high uniform magnetic field. However, the high magnetic field gradient showed more obvious effect on the alignment of the primary Al3Ni phases than the uniform magnetic field, although this effect strongly depended on the alloy composition.

Abstract: Quasicontinuum simulation of nanometric cutting was conducted on single crystal copper to investigate the effect of crystal orientation and cutting direction on nature of deformation of this material. The model reduces the degrees of freedom in simulations of nanometric cutting process without sacrificing important physics. The simulation results show the crystal orientation and cutting direction have a significant effect on the nature of deformation of nanometric cutting process. In addition, the variations of strain energy of workpiece atoms in different crystal set-ups are investigated.