Preferred Orientation in Nanocomposite Permanent Magnet Materials

Melt-spun （Nd11.4Fe82.9B5.7）0.99M1 ribbons （M = Zr, Nb, Ga, Zr＋ Ga, Nb ＋ Ga）were prepared by melt-spinning technique. Ga addition is found to be effective for the orientation of c-axis of Nd2Fe14B grains perpendicular to the ribbon plane. Better magnetic properties can be achieved by adding both the two kinds of elements Zr ＋ Ga, Nb ＋ Ga, and it is found that the preferred orientation is further improved. The alignment degree changes with ribbon thickness and is highest when ribbon thickness is 120 μm. Heat treatment can improve the texture degree, but lead to coarser grains. Cryogenic treatment is first applied for the treatment of nanocomposite Nd2Fe14B/α-Fe melt-spun ribbons. The effects on magnetic properties and texture degree of nanocomposite magnets after cryogenic treatment were studied. The result shows that cryogenic treatment is beneficial to the enhancement of texture degree of melt-spun ribbon and the grain size has no obvious change.

Relationship between crystal growth mode, preferred orientation and magnetostriction of (Tb_(0.3)Dy_(0.7))Fe_(1.95) alloys

The relationship between crystal growth mode, preferred orientation and magnetostrictive properties of （Tb0.3Dy0.7）Fe1.95 alloys was investigated at different directional solidification rates. The results showed that preferred orientation had a strong influence on the characteristics of （Tb0.3Dy0.7）Fe1.95 alloys. At lower solidification rates, the sample with 〈110〉 preferred orientation showed larger low-field magnetostriction and apparent compressive stress effect. The excessive solidification rate resulted in failure of preferred orientation and a poor magnetostrictive performance. With an increase in solidification rates, the crystal growth modes changed gradually from cellular and primary dendrite morphology to developed dendritic morphology. In addition, domain configurations were observed using magnetic force microscopy, and the change of magnetostrictive properties was interpreted in terms of revealing the domain configurations.

PREFERRED ORIENTATION OF DEPOSITED TiC COATING ON STEEL BY CVD

Investigation was made of the deposited rate,surface morphology and crystal pre- ferred orientation of the dense TiC coating onto austenitic stainless steel in relation with CH_4/TiCl_4 mole ratio and temperature adopted in CVD processing. When the CH_4/TiCl_4 ratio is low or high,the preferred orientation may be(220)or(200),respec- tively,which is mainly dependent on the equilibrium concentration of active C in vapour phase.

Environmental Embrittlement and Preferred Orientation of Cold-Rolled and Annealed Fe_3 (Al,Cr,Zr) Alloy at Ambient Temperature

The room temperature tensile properties of cold rolled and annealed Fe 3(Al,Cr,Zr) alloy are similar to those of warm rolled Fe 3Al alloys. The cold rolled Fe 3(Al,Cr,Zr) alloy is also susceptible to test environments. It has been shown that the ductility in various environments decreases in sequence of oxygen—oil—air—distilled water. The results of X ray diffraction analysis show that (211) preferred orientation of B 2 phase appears in cold rolled Fe 3(Al,Cr,Zr) alloy after recrystallization annealing.

Enhanced Ferroelectric Polarization in Laser-ablated Bi4Ti3O12 Thin Films by Controlling Preferred Orientation

Polycrystalline Bi_4Ti_3O_（12） thin films with various fractions of a-axis, c-axis and random orientations have been grown on Pt（111）/Ti/Si O_2/Si substrates by laser-ablation under different kinetic growth conditions. The relationship between the structure and ferroelectric property of the films was investigated, so as to explore the possibility of enhancing ferroelectric polarization by controlling the preferred orientation. The structural characterization indicated that the large growth rate and high oxygen background pressure were both favorable for the growth of non-c-axis oriented grains in the Bi_4Ti_3O_（12） thin films. The films with high fractions of a-axis and random orientations, i e, f（a-sxis） = 28.3% and f（random） = 69.6%, could be obtained at the deposition temperature of 973 K, oxygen partial pressure of 15 Pa and laser fluence of 4.6 J/cm^2, respectively. It was also noted that the variation of ferroelectric polarization was in accordance with the evolution non-c-axis orientation. A large value of remanent polarization（2 Pr = 35.5 μC/cm^2） was obtained for the Bi_4Ti_3O_（12） thin films with significant non-c-axis orientation, even higher than that of rare-earth-doped Bi_4Ti_3O_（12） films.

Lattice Preferred Orientation, Water Content, and Seismic Anisotropy of Orthopyroxene

Lattice preferred orientation （LPO） and seismic anisotropy of orthopyroxene （enstatite） in mantle xenoliths from Spitsbergen, Svalbard, near the Arctic, are studied. LPOs of enstatite were determined using electron backseattered diffraction （EBSD）. We found four types of LPOs of orthopyroxene and defined them as type-AC, -AB, -BC, and -ABC. Type-AC LPO of orthopyroxene is defined as （100） plane aligned subparallel to foliation and [001] axis aligned subparallel to lineation. Type-AB LPO is defined as （100） plane aligned subparallel to foliation and [010] axis aligned subparallel to linea- tion. Type-BC LPO is defined as （010） plane aligned subparallel to foliation and [001] axis aligned subparallel to lineation. Type-ABC LPO is defined as both （100） and （010） planes aligned subparallel to foliation with a girdle distribution of both [100] and [010] axes normal to lineation and [001] axis aligned subparallel to lineation. We report for the first time the type-AB, -BC, and -ABC LPO of orthopyroxerie. We found that the LPO pattern has a correlation with the content of orthopyroxene in the specimen. Nicolet 6700 FTIR （Fourier transformation infrared） study of enstatite showed that type-AC LPO was observed mostly in the samples of enstatite with low water content. It is found that the strength of the LPO of enstatite decreases with increasing water content and has a correlation with the strength of the LPO of olivine： the stronger the LPO of enstatite, the stronger the LPO of olivine. Seismic anisotropy of enstatite was smaller than that of olivine in the same specimen.

Efficient Preparation of Nanoparticle-Reinforced Nickel-based Composite Coating with Highly Preferred(220)Orientation

Nanoparticle-reinforced metal matrix composite coatings have significant potential in mechanical part surface strengthening owing their excellent mechanical properties.This paper reports a phenomenon in which the grain orientation gradually evolves to(220)as the deposition current density increases when preparing nanoparticle-reinforced nickel-based composite coatings through jet electrodeposition(JED).During the preparation of the Ni-SiC composite coatings,the deposition current density increased from 180 A/dm2 to 220 A/dm2,and TC(220)gradually increase from 41.4%to 97.7%.With an increase of TC(220),the self-corrosion potential increases from−0.575 to−0.477 V,the corrosion current density decreases from 9.52μA/cm^2 to 2.76μA/cm^2,the diameter of the corrosion pits that after 10 days of immersion in a 3.5 wt%NaCl solution decreases from 278–944 nm to 153–260 nm,and the adhesion of the coating increases from 24.9 N to 61.6 N.Compared a conventional electrodeposition(CED),the Ni-SiC composite coating using JED has the advantages of a smooth surface morphology,high corrosion resistance,and strong adhesion,which are more obvious with an increase in TC(220).

Intense red emitting mechanoluminescence from CaZnOS:Mn,Li with c-axis preferred orientation

We report that the co-doping of Li^(+)ions significantly enhances the crystallinity and mechanoluminescence(ML)intensity of CaZnOS:Mn.The prepared CaZnOS:Mn,Li showed a preferred orientation of c-axis,and the particles possessed a plate-like morphology,which could be attributed to the layered structure of CaZnOS.At the same time,the ML induced by compressive load exhibited intense red emission and obvious intensity enhancement by the Li^(+)co-doping.

Preferable Orientations of Interacting C_(60) Molecules inside Single Wall Boron Nitride Nanotubes

This work focuses on the preferable orientation analysis of the hybrid system where the C60 molecules are encap- sulated inside the boron nitride nanotubes by using the two-molecule model. The low-energy state can be acquired in the contour map, which provides the visual information of the systematical van der Waals interaction potential for the C60 molecules adopting different orientations. Our results show that the C60 molecules exhibit the pre- ferred pentagon and hexagon orientations with the tube＇s diameter smaller and larger than 13.55A, respectively. The preferred two-bond orientation obtained in the single-molecule model is absent in this study, indicating that the intermolecular interaction of adjacent C60 molecules plays an important role in the orientational behaviors of this peapod structure.

The preferences of orientations between the pairs of amino acids

In this work, we make an investigation on the preferences of orientations between amino acids using the orientation defined based on the local geometry of the amino acids concerned. It is found that there are common preferences of orientations （70°, 30°, 140°） and （110°, 340°, 100°） for various pairs of amino acids. Different side chains may strengthen or weaken the common preferences, which is related to the effect of packing. Some amino acids having specific local flexibility may possess some preferences of orientations besides the common ones, such as （10°, 280°, 210°）. Another analysis on the pairs of the amino acids with different secondary-structure preferences shows that the directional interaction may affect the distribution of orientation more effectively than the packing or local flexibility. All these results provide us some insight of the organization of amino acids in protein, and their relation with some related interactions.

Mechanical properties of electroformed copper layers with gradient microstructure

The electroformed copper layer with gradient microstructure was prepared using the ultrasonic technique. The microstructure of the electroformed copper layer was observed by using an optical microscope （OM） and a scanning electron microscope （SEM）. The preferred orientations of the layer were characterized by X-ray diffraction （XRD）. The mechanical properties were evaluated with a Vicker＇s hardness tester and a tensile tester. It is found the gradient microstructure consists of two main parts： the outer part （faraway substrate） with columnar crystals and the inner part （nearby substrate） with equiaxed grains. The Cu-（220） preferred orientation increases with the increasing thickness of the copper layer. The test results show that the microhardness of the electroformed copper layer decreases with increasing grain size along the growth direction and presents a gradient distribution. The tensile strength of the outer part of the electroformed copper layer is higher than that of the inner part but at the cost of ductility. Meanwhile, the integral mechanical properties of the electroformed copper with gradient microstrucmre are significantly improved in comparison with the pure copper deposit.

Texture of deformed Cu-Cr-Zr alloys

The influences of plastic deformation, aging treatment, and alloying elements on the texture of Cu-Cr-Zr alloys were ex- plored. The texture component and intensity of Cu-Cr-Zr alloys under various working conditions after aging treatment were characterized using the orientation distributing function （ODF）. The influence of Zr content on the texture of Cu-Cr-Zr alloys was also analyzed. The reduction pass and deformation level were primary factors influencing the texture. Rolling texture appeared in a rolled plate and the fibrous textures of {111} and {001} were detected after 80% deformation. Fibrous texture with a main constituent of {111} improved the tensile strength of the alloy wire. The texture contents of {110}〈331〉 and {110}〈112〉 were predominated, whereas, those of {113}〈332〉 and {112}〈111〉 were in the minority in the Cu-Cr-Zr alloy with a higher Zr content （〉0.5wt%）. However, in the samples with a lower Zr content （〈0.1wt%）, the texture contents of {113}〈332〉, {112}〈111〉, and {111}〈110〉 were in the majority.

THE EFFECTS OF NEGATIVE BIAS AND FLUX RATIO ON THE PROPERTIES OF TiN THIN FILMS FORMED BY FILTERED CATHODIC ARC PLASMA TECHNIQUE

The filtered cathodic vacuum-arc (FCVA) technique is a supplementary and alterna tive technique with respect to convendtional physical and chemical vapour deposi tion which can remove macro-particles effectively and make the deposition proces s at ambient temperature. In this work, high quality TiN thin films were deposi ted on silicon substrates at low temperature using the improved filtered cathodi c arc plasma (FCAP) technique. AFM, XRD, TEM were employed to characterize the T iN thin films. The effects of the negative substrate bias on the grain size, pre ferred crystalline orientation, surface roughness of TiN thin films were discuss ed.

Determination and Significance of the Bluemull Blastomylonite Zone in the Northeast——East of Yell,Shetland

There is a zone of blastomylonites containing hornblende gneisses of Lewisian Inlier type in the northeast - east of Yell , Shetland . This zone with a north - northwesterly trend consists of blastomylonised hornblende - banded gneiss , hornblende - feldspar gneiss and mica - felsic - gneiss with lenses of hornblende gneiss . It is indicated that the blastomylonite zone is actually a ductile shear zone and the sense of shear is dextral . This contributes to understanding the details of tectonic evolution in this area , and this zone is probably a part of tectonic system of the British Caledonides .

Fabrication processing effects on the microstructure and morphology of erbium film

The effect of substrate temperature on the microstructure and the morphology of erbium film are systematically investigated using X-ray diffraction （XRD） and scanning electron microscopy （SEM）. All the erbium films are grown by electron-beam vapor deposition （EBVD）. A novel preparation method for observing the cross-section morphology of the erbium film is developed. The films deposited at 200 ℃ have （002） preferred orientation, and the films deposited at 450 ℃ have a mixed （100） and （101） texture, due to the different growth mechanisms of surface energy minimization and recrystallization, respectively. The peak positions and the full widths at half maximum （FWHMs） of erbium diffraction lines （100）, （002）, and （101） shift towards higher angles and decrease with the increasing substrate temperature in a largely uniform manner, respectively. Also, the lattice constants decrease with increasing temperature. The transition in the film stresses can be used to interpret the changes in peak positions, FWHMs, and lattice constants. The stress is compressive for the as-growth fihns, and is counteracted by the tensile stress formed during the process of temperature cooling to room temperature. The tensile stress mainly originates from the difference in the coefficients of thermal expansion of the substrate-film couple.

Texture of Magnetron Sputter-deposited 1Cr18Ni9Ti Stainless Steel

Phase transformation of magnetronsputter deposited 1Cr18Ni9Ti stainlesssteel has been studied [1]. A single bccphase was formed as the substrate tempera-ture kept below 370℃. The deposits exhibited different textures,which depended on the position of the subs-trates relative to the target: the predominant(110) planes were parallel to the surfaceof substrate which was parallel to the target:the predominance was weakened whenthe substrate surface was vertical to the

Charge and discharge curves:a unique reliable evidence for the electrochemical properties of LiCoO_2

X-ray diffraction （XRD）, the traditional characterization method to detect the electrochemical properties of LiCoO2, was doubted. The XRD patterns of three types of LiCoO2, with similar electrochemical properties, present differences. For the same type of LiCoO2, different XRD patterns were obtained when the sample preparing methods were different, because of preferred orienta- tion. The nonstandard method to prepare XRD powder samples can eliminate preferred orientation. The reliable evidence to detect electrochemical properties is still charge and discharge curves.

Mechanical Properties, Metallurgical Characteristics and Anisotropy of Additive Manufacturing of 316L

Additive manufacturing (AM), while enabling the production of parts with complex geometries, presents new challenges. In particular, the achievement of the basic mechanical properties of the alloy must be ensured. In general, the strength-ductility properties of metals depend strongly on their microstructure, and controlling these properties requires paying attention to the alloy composition, processing technique and heat treatments. Austenite 316L stainless steel parts produced by AM demonstrate good ductility and high yield strength—higher than that obtained with annealed 316L. Some preferred orientation of the mechanical properties was found as a function of the laser path, namely, the Young’s modulus varied with respect to the angle between the build direction and the normal to the build direction. In the present study, samples of AM 316L in three orientations relative to the print direction (0˚, 45˚and 90˚) are compared to a forged sample. Mechanical properties, scanning electron microscopy-SEM fractography, energy dispersive X-ray spectroscope-EDS analysis of the fracture and optical cross section images of the samples along the stress tension after the failure are presented.

Effects of Electropulsing Induced Microstructural Changes on THz-Reflection and Electrical Conductivity of Al-Doped ZnO Thin-Films

Electropulsing induced phase transformation and crystal orientation change and their effects on electrical conductivity, THz reflection and surface roughness of thin-films of Al2O3 (2 wt%) doped ZnO were studied using XRD, SEM, AFM and Thz spectroscopy techniques. AZO-2 thin-films showed an effective response in THz spectroscopy under electropulsing. Electropulsing induced circular preferred crystal orientation changes and phase transformations were observed. The preferred crystal orientation changes accompanying decrease in stress and the secondary phase precipitation favored enhancing conductivity and THz reflection of the AZO-2 thin-films. After adequate electropulsing, both THz reflection and electrical conductivity of the thin-films were enhanced by 22.8% and 6.8%, respectively;meanwhile surface roughness reduced. The property responses of electropulsing are discussed from point view of microstructural change and dislocation dynamics.

X-ray diffraction analysis by Rietveld refinement of FeAl alloys doped with terbium and its correlation with magnetostriction

Fe_(81)Al_(19) polycrystalline alloys doped with Tb(0-0.25 at%) were obtained by arc melting.The introduction of Tb favors the formation of columnar grains in the micro structure of the alloys,which develops a texture in the [100]crystal direction.Microstructural examination shows that the alloys are composed in great proportion by the disordered body-centered cubic(bcc),A2 phase and by a small proportion of the ordered bcc,B2 phase.As a consequence of doping with Tb,the lattice parameter increases,so the calculated apparent crystallite size increases,indicating a decrease in dislocation density and therefore in microstrains.The change in the magnetostriction with the magnetic field,dλ_(T)/dH,is directly related to strain anisotropy that can favor the iron easy magnetization axis on the [100] direction.An increase in total magnetostriction is found in the doped alloys with a maximum of 90 × 10^(-6) at 300 K for the alloy containing 0.027 at% Tb.This enhancement is a threefold value of the undoped alloy,which is attributed to the smaller maximum strain value and the preferential orientation formation by the columnar grains.