Showing papers on "Texture (crystalline) published in 1978"
TL;DR: In this paper, the texture of raw and soaked cowpeas (Vigna unguicuiata) was measured using a wedge-type blade mounted in an Instron testing machine to cut across the cotyledons.
Abstract: A method has been developed to measure the texture of raw and soaked cowpeas (Vigna unguicuiata) using a wedge-type blade mounted in an Instron testing machine to cut across the cotyledons. It was found that soaking raw cowpeas in water prior to cooking produced a softer bean and the decrease in hardness was proportional to the soaking time. Texture of cooked beans could be predicted from the texture of the corresponding soaked bean. The influence of cooking temperature and time on bean texture was studied using the shear-compression cell of - the Texture Test System and the Ottawa Texture Measuring System cell with a wire extrusion grid. It was found that the rate of cooking relative to texture followed first order kinetics. Scanning electron microscopy was used to study changes in microstructure during the cooking process. The major effect observed was a breakdown of the middle lamella; cell walls remained intact.
114 citations
TL;DR: In this paper, a detailed analysis by reflection electron diffraction (RED), x-ray diffraction and scanning electron microscopy (SEM) was performed on thin ZnO layers which were formed under reactive and nonreactive rf•sputtering conditions.
Abstract: Detailed analysis by reflection electron diffraction (RED), x‐ray diffraction (XRD), and scanning electron microscopy (SEM) was performed on thin ZnO layers which were formed under reactive and nonreactive rf‐sputtering conditions. A variety of textures and morphologies were observed. 100% reproducible piezoelectric layers, preferred oriented with [002] perpendicular to the layer within 7°, could be obtained by reactive sputtering from a zinc target at rf power of 150 W, oxygen‐argon atmosphere of 8×10−3 Torr with 35% O2, and with the glass substrate being kept at room temperature by a cooling device. No differences in the surface‐acoustic‐wave properties were found between reactively and nonreactively sputtered ZnO layers which had similar texture and morphology. SEM techniques proved to be extremely misleading in the study of this type of layer; there is no relationship between an observed columnar structure and the texture of the layer which is determined by RED, and also between the column thickness (...
105 citations
TL;DR: In this article, it was shown that alladium layers in the thickness range 0.1-15 monolayers were deposited by evaporation onto the polar ZnO(0001)Zn and (0001)O surfaces.
45 citations
TL;DR: In this article, reversible hydration of amorphous V 2 O 5 has been performed in order to study the effect of water upon the properties of the oxide, which turns from anisotropic to isotropic upon hydration.
42 citations
TL;DR: In this article, the growth of cracks in Ti-6Al-4V alloy was studied in fatigue tests in which the maximum load each cycle was held constant for a chosen dwell-time, and the results were compared with those obtained using sinusoidal stressing.
37 citations
TL;DR: The reflectance of silicon measured at 4.3 eV can be used to determine the surface quality of silicon and is readily adaptable to quality control inspection in silicon device manufacturing facilities.
Abstract: The reflectance of silicon measured at 4.3 eV can be used to determine the surface quality of silicon. Crystallographic damage, which occurs with abrasive polishing, and texture, which occurs with epitaxial film growth, can be detected. The effect of surface damage on the optical reflectance of silicon measured at 4.3 eV is reported. The reflectance measurement is nondestructive, simple, fast (on the order of seconds), and sensitive. The technique is readily adaptable to quality control inspection in silicon device manufacturing facilities.
36 citations
TL;DR: In this paper, the influence of grain orientation on the superplastic flow of Zn-22 %Al has been examined on specimens of similar microstructure but with different textures, and it was shown that the formation of a favorable texture leads to a decrease in flow stress, an increase in plasticity and a shift of the optimum rate region to higher strain rates.
29 citations
TL;DR: In this article, an X-ray texture parameter was developed for polycrystalline β-alumina and related to the measured anisotropy in sodium ion conduction for hot-pressed material.
28 citations
Journal Article•
25 citations
IBM1
TL;DR: In this article, the influence of target texture on the backscattering yield of 2 MeV 4 He particles has been investigated for evaported thin-film targets of Nb, Ag, Au and Bi.
21 citations
TL;DR: Fracture toughness tests have been carried out on a wide range of specimen orientations from textured Ti-6A1-4V alloy plate, and the results were discussed in terms of a qualitative analysis of slip systems at the crack tip and also in a semiquantitative upper bound slip line treatment as mentioned in this paper.
Abstract: Fracture toughness tests have been carried out on a wide range of specimen orientations from textured Ti-6A1-4V alloy plate. The tests were instrumented to allow measurement of crack extension as well as stress intensity factors and COD data. Preferred orientation of the dominant alpha phase was found to influence not only the toughness parameters but also the fracture surface and propensity to shear lip formation. The anisotropic nature of plasticity in the material was demonstrated by direct measurement of yield loci and by the variable shapes of plastic zones around crack tips. Results are discussed in terms of a qualitative analysis of slip systems at the crack tip and also in a semiquantitative anisotropic upper bound slip line treatment. It is found that stable crack extension starts at low values ofK and COD for specimens in which plastic flow can occur readily at the crack tip but toughness, assessed as resistance to unstable crack propagation, is greatest in these cases. The magnitude of microstructure induced anisotropy is shown to be much smaller than that originating in preferred crystallographic orientation. Troughlike features on some fracture surfaces were found to be associated with regions of particularly strong local texture.
TL;DR: In this paper, the formation process of bubble domains in a large pitch cholesteric is investigated under various circumstances. But the bubble domains are formed through the inherent or field-induced striped texture.
Abstract: The forming process of bubble domains observed in a large pitch cholesteric is investigated under various circumstances. In this experiment the bubble domians of a negative dielectric anisotropy are formed by an application of an electric field below that required for dynamic scattering. The domains of a positive dielectric one are formed by applying thermal turbulence. It is found that the bubble domains are formed through the inherent or field-induced striped texture. The change from stripe to bubble and the reversed change are directly observed. These observations allow one to determine the molecular alignment in the domains. The stability of bubble domains also is discussed.
TL;DR: In this article, a generalized crystal-plasticity phenomenon that is applicable to any material in which texture-orientation banding or clustering effects occur was proposed. But the mechanism may be one of several possible causes of fracture in high-strength alloy-steel plates when fractured dynamically.
Abstract: Texture banding is common in sheet steels, especially in highly alloyed steels. Anisotropie plastic flow during tensile straining is known to cause cold-rolled and annealed ferritic-stainless-steel sheet to exhibit “ridging” or “roping” in the plane of the sheet even though there is no banding due to grain size, carbides, or inclusions. It has been observed that groups of grains having a common crystallographic orientation can appear in ribbon-like form and can result in anisotropic banding. In ferritic stainless steel, such bands frequently consist of the cube-on-face texture component imbedded as layers in a cube-on-corner matrix. In the present study, it was demonstrated that in tensile deformation, such “texture” banding results in anisotropic plastic flow, causing thin sheet to ridge on the surface, and thick sheet to develop cracks that propagate in planes parallel to the sheet surface. In this study, room-and low-temperature tension tests were conducted at low and high strain rates on samples of thin and thick AISI Type 430 ferritic-stainless-steel sheet, and room-temperature impact tests were conducted on the thick sheet. The results showed that, at low temperature or high strain rates, the banded cube-on-face texture component imbedded in other matrix orientations, such as the cubeon-corner texture, or a purely cube-on-face textured matrix, tends to cause lamellar fracture of the sheet. This was especially true in thick sections. The proposed mechanism is a generalized crystal-plasticity phenomenon that is applicable to any material in which texture-orientation banding or clustering effects occur and the mechanism may be one of several possible causes of “splitting” which is sometimes observed in highstrength alloy-steel plates, such as line-pipe plates, when fractured dynamically.
Patent•
03 Feb 1978
TL;DR: A body having a siliceous surface provided with a surface texture comprising predominantly a plurality of microvilli or whiskers projecting from and grown onto the surface is useful as a solid stationary phase for chromatography as discussed by the authors.
Abstract: A body having a siliceous surface provided with a surface texture comprising predominantly a plurality of siliceous microvilli or whiskers projecting from and grown onto the surface is useful as a solid stationary phase for chromatography.
TL;DR: In this article, the problem of relating the fundamental elastic properties of anisotropic single crystals to those of polycrystalline bulk materials is discussed, and it is shown that the orientationindependent relationships are not in fact independent of each other and are insufficient to enable the constants to be found.
Abstract: The author discusses the problem of relating the fundamental elastic properties of anisotropic single crystals to those of polycrystalline bulk materials. It is shown that the orientation-independent relationships are not in fact independent of each other and are insufficient to enable the constants to be found. Some useful results do, however, follow. Thus, the methods of Reuss (1929), Voigt (1928), and Hill (1952), lead to the same calculation of bulk modulus for polycrystalline materials and show that it should be identical with the single-crystal value. It is also shown why polycrystalline cubic metals behave in an isotropic manner when the grains are completely randomly oriented. Departures from randomness (development of an orientation texture) render increasingly invalid the widely accepted relationship between the moduli, E and G, and v (Poisson's ratio), viz. E=2G(1+v).
TL;DR: In this paper, the authors used linear regression analysis technique to correlate the Ti-6Al-4V stress-corrosion cracking data, KSCC, mechanical properties data, and metal-lurgical characteristics including variations in composition, microstructure, and basal plane crystallographic texture.
Abstract: Ti-6Al-4V stress-corrosion cracking data, KSCC, mechanical properties data, and metal-lurgical characteristics including variations in composition, microstructure, and basal plane crystallographic texture were correlated using linear regression analysis technique. The test data, representing 46 commercial heats of duplex-annealed material, exhibited variations in KSCC values from approximately 20 to over 100 ksi-in.1/2 (approximately 22 to over 110 MPa-m1/2). Regression analyses resulted in several equations that showed good correlations of KSCC values to metallurgical parameters. The regression analysis equations showed the most significant metallurgical parame-ters controlling KSCC to be oxygen content, texture, and alpha phase ordering (alpha phase ordering was found to be promoted by oxygen). Relatively high oxygen contents, strong textures, and high degrees of ordering were responsible for low values of KSCC.
TL;DR: In this paper, the elastic moduli of polycrystalline aggregates with texture are calculated and the upper and lower bounds coincide for some of the moduli, and the systematics of this effect is explained for the case of ideal fibre texture.
Abstract: In calculating bounds for the elastic moduli of polycrystalline aggregates with texture, one often observes that the upper and lower bounds coincide for some of the moduli. The systematics of this effect is explained for the case of ideal fibre texture. The effect is related to' the observation that textured polycrystals can exist in stress—strain states that are homogeneous even on the microscale.
TL;DR: In this article, the relationship between the crystallographic texture exhibited by commercially doped powder metallurgy (C.D.P.M.) tungsten wires and rods and the nature of the grain boundaries within the material was investigated.
TL;DR: In this article, electrical resistivity and magnetoresistance measurements from 4K to 300K on Metglas 2605 and Metglas2605 A are reported, and the anisotropic magnetoresistivity was found to increase with decreasing temperature.
Abstract: Electrical resistivity and magnetoresistance measurements from 4K to 300K on Metglas 2605 and Metglas 2605 A are reported. For both materials a resistivity minimum appears at low temperatures. Below the minimum an approximately logarithmic increase of resistivity was found. Magnetoresistance measurements were used to get additional information about the electronic conduction, magnetic texture and the nature of the magnetization process in these alloys. The anisotropic magnetoresistivity was found to increase with decreasing temperature.
TL;DR: In this paper, the authors examined the induced patterns under ac. electric field in dilute cholesteric and nematic mixtures with the negative dielectric anisotropy.
Abstract: The induced patterns under ac. electric field are examined in the dilute cholesteric and nematic mixtures with the negative dielectric anisotropy. The instability in the planar texture is triggered by a material flow at threshold voltage and regular periodic patterns can be observed by using the polarizing microscope. The patterns are deformed due to the formation of axial disclinations with increasing the field. The deformation is stabilized by making the new planar texture under the applied field. The number of twists increases in the new planar texture. When we increase the field further, the instability occurs in the new planar texture. A new mechanism for succeeding transitions is proposed. Both the electrohydrodynamic instability and the contraction of the cholesteric pitch are important in the mechanism.
TL;DR: In this article, anomalies in line intensities of Mossbauer absorbers subjected to non-hydrostatic pressure are attributed to texture, and the dependence of the texture function on the deformation of the sample and on the shape of the crystallites is calculated.
Abstract: Anomalies in line intensities of Mossbauer absorbers subjected to non-hydrostatic pressure are attributed to texture The dependence of the texture function on the deformation of the sample and on the shape of the crystallites is calculated From the texture function the asymmetry of a 1/2→3/2 quadrupole doublet is determined The possibilities of avoiding texture effects in Mossbauer spectroscopy are discussed and a method is suggested for preparing texture-free absorbers
Patent•
24 Apr 1978
TL;DR: In this article, a solar collector plate made of stainless steel or a metal having a nickel-flash coating is immersed in a molten dichromate salt bath at a temperature between about 375° C and about 500° C. sufficiently long to provide a selective oxide coating which has a Figure of Merit of at least about 4.
Abstract: A solar collector plate made of stainless steel or a metal having a nickel-flash coating is immersed in a molten dichromate salt bath at a temperature between about 375° C. and about 500° C. sufficiently long to provide a selective oxide coating which has a Figure of Merit of at least about 4. The oxide coating is continuous, has a microscopically nodular texture with the average nodule size being at least about 5000 A and displays a Figure of Merit of at least about 4.
Patent•
16 Mar 1978
TL;DR: In this article, a process for producing electromagnetic silicon steel having a cube-on-edge orientation is described, which includes the steps of: preparing a melt of silicon steel with up to 0.07% carbon, from 0.01-0.09% of material from the group consisting of sulfur and selenium, from 2.5 to 4.0% silicon, up to 1.009% aluminum and less than 0.0006% boron.
Abstract: A process for producing electromagnetic silicon steel having a cube-on-edge orientation. The process includes the steps of: preparing a melt of silicon steel having up to 0.07% carbon, from 0.01 to 0.25% manganese, from 0.01 to 0.09% of material from the group consisting of sulfur and selenium, from 2.5 to 4.0% silicon, up to 1.0% copper, less than 0.009% aluminum and less than 0.0006% boron; casting the steel; hot rolling the steel; cold rolling the steel; normalizing the steel in a hydrogen-bearing atmosphere having a pH2 O/pH2 of from 0.015 to 0.3; applying a refractory oxide coating containing an oxide less stable than SiO2 at temperatures up to 2150° F.; and final texture annealing the steel.
TL;DR: In this article, the formation of new planar regions during the electrohydrodynamic distortion of the cholesteric planar texture in liquid crystals with a negative dielectric anisotropy was studied.
Abstract: 2014 A study is made of the formation of new planar regions during the electrohydrodynamic distortion of the cholesteric planar texture in liquid crystals with a negative dielectric anisotropy. With increasing voltage successive planar regions are observed which are associated with an increasing number of helices across the layer with steady planar boundary conditions. The resulting pitch contraction occurs via discontinuities which can be related to S = (1) disclinations. The stability of the new planar regions if favoured by a large negative dielectric anisotropy. The threshold voltage for the square grid perturbation of these induced textures is much larger than that predicted theoretically by Helfrich and Hurault, whose theory only holds for cholesteric planar layers in which the natural pitch P0 occurs. LE JOURNAL DE PHYSIQUE ’ TOME 39, AVRIL 1978,
TL;DR: In this paper, the pole figures measured by Bauer, Mecking and Lucke on rolled copper single crystals have been transposed into the 3-dimensional Eulerian orientation space and compared to the orientation distribution functions determined by Bunge, Tobisch and Sonntag for poly-crystalline copper.
TL;DR: In this article, the structure of electrodeposited cobalt coatings has been studied by means of quantitative X-ray methods to determine the amounts of h.p. and f.c. phases in the presence of texture, the perfection, the particle size and the microstrain.
TL;DR: In this article, the authors applied a topology based on neutron diffraction topography to the direct observation of the texture in Bridgman-grown Cu-5% Ge crystals with growth direction nearly parallel to [110].
Abstract: Neutron diffraction topography has been applied to the direct observation of the texture in Bridgman-grown Cu-5% Ge crystals with growth direction nearly parallel to [110]. The texture is composed of a layer substructure, constituting a hierarchy in the crystal texture: layers parallel to (001) are arrayed with the spacing of about 1 mm, and extend throughout the crystal nearly parallel to the growth direction. The (001)-layers are attached on both sides with plates parallel to (100)- and (010)-planes. These layer substructures correspond to the arrayed striations visible on the crystal surfaces. The substructure is different from both the cellular and the lineage substructures hitherto proposed to describe the texture of Bridgman-grown crystals. The model suggests a new type of growth mechanism along three kinds of {100}-planes. The novel techniques of neutron diffraction topography are described. In the Appendix, the observed image contrast of the topographs is shown to be explained by the diff...
15 Mar 1978
TL;DR: The structural changes occurring during warm working of Cd-1.5 pct Zn alloy and their effect on the subsequent mechanical properties are studied in this paper, where it is observed that changes in grain size and preferred orientation are important to a large extent in controlling the mechanical strength.
Abstract: The structural changes occurring during warm working of Cd-1.5 pct Zn alloy and their effect on the subsequent mechanical properties are studied. It is observed that changes in grain size and preferred orientation are important to a large extent in controlling the mechanical strength. The Hall-Petch slope,R decreases in the warm worked material while the friction stress, σo increases. The lowerR values are attributed to the development of a (101l) texture and the higher σo values are interpreted on the basis of changes in the basal texture.