Major Texture Components Research Articles

Determination of crystallographic texture in cold-rolled copper and stainless steel by spectrum analysis of ultrasonic signal

A new approach to analyze the ultrasonic signal using the birefringence effect for texture analysis has been attempted for determining major texture components in copper and stainless steel in annealed and cold-rolled conditions. Results of ultrasonic signal analysis have been compared with the texture studied by conventional X-ray diffraction technique . It has been found that the spectrum analysis of windowed ultrasonic signal can be a non-destructive tool to determine the major texture components in deformed materials.

Characterization of texture and microstructure of electrodeposited Ni layers

AbstractThe texture and microstructure of electrodeposited Ni layers formed in an additive-free Watt's bath were investigated. The microstructure of the electrodeposited Ni layer consists of fine columnar grains extending along the growth direction. The major texture components of electrodeposited Ni layers on Ni-P substrate were (112) and (110) fibers. On the other hand, electrodeposited Ni layers on Cu substrate had a strong (110) fiber texture. In the vicinity of the interface between the electrodeposited Ni layer and the Cu substrate, obvious epitaxial regions were not observed. Many twins parallel to the growth direction were observed in the electrodeposited Ni layer. It is suggested that grains with a twin relationship grew preferentially during the electrodeposition reaction.

Recrystallisation Behavior of Cold Rolled Zr702: Influence of Rolling Direction and Thickness Reduction

Zirconium alloys are widely used for different applications in nuclear industry. Precise knowledge of their texture is of great relevance since this hcp metal exhibits a strong crystal anisotropy. Despite that, the mechanisms of texture change during its deformation and subsequent annealing are still not precisely known. Thus, there is a need for a better understanding of the fundamental mechanisms of recrystallisation. Earlier works on Zr702 [1-3] suggested that the kinetics and local mechanisms of recrystallisation after cold-rolling was controlled by the heterogeneity of the deformed microstructure and that, at the end of recrystallisation (corresponding to the disappearance of the deformed matrix), the position of the major texture components remained almost unaffected. The aim of the present work is to confirm whether these statements can be generalized for various deformation conditions or not.

Annealing Texture and Microstructure Evolution in Titanium during Grain Growth in an External Magnetic Field

The impact of a magnetic field (17T) on texture and microstructure evolution in cold rolled (75%) commercially pure titanium was investigated. The specifically oriented titanium sheet specimens were heat treated at 1023 K in a magnetic field of 17 T for 60, 120, 180 and 240 minutes. X-ray diffraction and EBSD measurements were utilized to characterize the crystallographic texture and the grain microstructure. The magnetic annealing resulted in an asymmetry of the two major texture components that constantly increased with annealing time. This effect is attributed to a magnetic driving force for grain growth arising from the anisotropic magnetic susceptibility of titanium. Complementary computer simulations of 2D grain growth were employed to analyze the effect of a magnetic field on texture and microstruture evolution. EBSD measurements as well as the computer simulations revealed that a magnetic field affects the grain growth kinetics. Grains with energetically preferred orientations grow faster and their fraction becomes larger than the fraction of more slowly growing grains with disfavored orientations.

Fabrication of TFA-MOD YBCO Films Using the Y<sub>2</sub>Ba<sub>1</sub>Cu<sub>1</sub>O<sub>x</sub> and Ba<sub>3</sub>Cu<sub>5</sub>O<sub>8</sub> Powders

We fabricated YBCO film using a TFA-MOD method and evaluated the phase formation, texture evolution, and critical properties as a function of the firing temperatures. In order to enhance the reaction kinetics and to control the formation of the second phases, Y2Ba1Cu1Ox and Ba3Cu5O8 powders were used as precursors (the so called “211 process”), instead of Y-, Ba-, and Cu-based acetate, and dissolved in trifluoroacetic acid (TFA). The films were calcined at 460°C and then fired at 750°C-800°C in a 12.1% humidified Ar-O2 atmosphere. We found that the microstructure varied significantly with the firing temperature; the grain grew further and the film became denser as the firing temperature increased. The textures of all of the films were similar and mainly biaxial. On the other hand, the intensity of the major and minor texture components differed from each other. For the film fired at 775°C, the critical current was obtained to be 39 A/cm-width (corresponding critical current density is 2.0 MA/cm2), which was probably attributed to such factors as the enhanced phase purity and out-of-plane texture, the moderate film density and grain size, and crack-free surface.

EBSD texture analysis of a high temperature gas nitrided duplex stainless steel

An electron back scattering diffraction characterization analysis of a high temperature gas nitrided UNS S31803 duplex stainless steel was performed. Nitriding treatments were carried out between 1423 and 1473 K, for times varying between 0.18 and 86.4 ks, under nitrogen partial pressures varying between 0.03 and 0.15 MPa. Upon investigation, these samples displayed a fully austenitic surface layer on a ferritic–austenitic duplex core. The grain boundary character distribution of surface austenitic layers strongly varied as the nitriding parameters were varied; low- ΣCSL grain boundary fractions between 0.35 and 0.65 were obtained. Conversely, the microtexture mainly depended on nitriding time, being only slightly affected by nitrogen partial pressure or temperature changes. At the earliest stages of nitriding, austenitic cases displayed an intense microtexture with two major texture components, {0 0 1}〈1 0 0〉 and {0 1 1}〈2 1 1〉, which weakened as nitriding time was increased.

Deformation-induced transformation textures in metastable austenitic stainless steel

Evolution of texture in metastable austenitic stainless steels under subzero rolling and cold rolling conditions is studied. The magnitude of strain-induced α′-martensite phase formed under subzero and subsequent cold rolling condition found to be larger than only cold rolling under same amount of deformation. Under both rolling conditions α′-martensite phase developed similar texture. On the other hand, the reverted austenite phase produced by ageing treatment has attained its parent cold rolling texture in the case of specimens which are only cold rolled. The corresponding reverted austenite phase from subzero and cold rolled specimen has indicated four major texture components which are typical of fcc metals and alloys. The reversion of α′-martensite observed in this study may be athermal in nature.

Effect of product form and heat treatment on the crystallographic texture of austenitic Nitinol

The superelastic material Nitinol, a nearly equiatomic alloy of nickel and titanium, is rapidly becoming one of the most important metallic implant materials in the biomedical industry, especially for the fabrication of endovascular stents. The manufacture of these stents, and countless other Nitinol products, originates from various forms of raw material such as tube, sheet or rod. However, depending upon which product form is used, the crystallographic texture in Nitinol can be significantly different, which can lead to marked changes in its mechanical properties. In this paper, we present a study to show the characteristic texture in various Nitinol product forms (tube, sheet, and rod), before and after annealing heat treatments, with specific quantification of the major texture components. We further present predictions of the mechanical response based upon such texture, and provide experimental verification with uniaxial tensile tests. Results show that the form of the starting material has a profound influence on characteristic texture and predicted mechanical response. Furthermore, annealing heat treatments, rather than reducing the texture, are found to increase the strength of this texture.

Application of Two-Point Orientation Auto-Correlation Fucntion (TP-OACF)

A two-point orientation auto-correlation function (TP-OACF) was developed in order to quantify the spatial distribution of targeted texture components. An example of a TP-OACF was demonstrated using an idealized orientation map. Characteristics of the spatial distribution of major texture components in 6022-T4 Al sheets deformed in plane-strain tension were also quantified using a TP-OACF. The results showed that {110}〈1\\bar12〉 and {123}〈63\\bar4〉 orientations (in {ND}〈PD〉 notation, where PD is the pulling direction) tend to form localized diagonal and horizontal bands through the thickness, respectively, after the plane-strain deformation. The cube orientation on the surface initially showed a relatively strong texture band along the RD, but this banding behavior was less significant after the plane-strain deformation.

Texture Evolution during Direct and Reversed Hot Torsion Tests of Stabilized Ferritic Stainless Steels

The study was carried out to understand the mechanisms occurring during the direct (negative shear direction) and reversed (positive shear direction) hot torsion of 11% chromium stabilized ferritic stainless steels. The behaviours induced by various types of stabilization, i.e., when either niobium, or titanium, or both niobium and titanium are used were compared. It was observed that continuous dynamic recrystallization (CDRX) operates in all materials starting at the onset of straining. Niobium has a more pronounced influence on hardening than titanium during hot deformation, which is due to solid solution strengthening and also to the reduction or stopping of grain boundary migration by solute drag effect. The D2 component, {112} < 111 > , was the major texture component at the steady state for the torsion tests carried along the negative shear direction. It was likely to be formed by a combination of strain and the growth of grains exhibiting both low stored energy and low rotation rate of the crystallographic axes. After reversion of the shear direction, i.e. during positive shear, the above major texture component is gradually changed into the D1 component, {112} < 111 > . Using the CMTP method (Continuum Mechanics of Textured Polycrystals), the stress evolution is explained by the volume fraction changes of each component at various strains, associated with their respective Taylor factors. Such simplified approach leads to a good agreement with experimental results.

The Effect of Initial Orientation and Rolling Schedule on Texture Development in Duplex Steel

A development of deformation textures was examined in ferritic-austenitic duplex type steel subjected to cold-rolling within the range up to 90% of reduction by applying different rolling schedules. The investigations included X-ray phase analysis, texture measurements and microstructure observations by means of light microscopy. The experimental results indicate at the occurrence of strong initial textures in both component phases after preliminary thermo-mechanical treatment. Formation of the ferrite-austenite banded structure in the course of rolling along with the stability of major texture components, related by Bain orientation relationship, exert considerable effect on the development of the ferrite and austenite rolling textures.

Effects of Dielectric Roughness on Texture of Both PVD Seed Layers and EP Copper

The ability to control the crystallographic orientation of both the seed layer and the electroplated copper grains is important in obtaining highly reliable Cu interconnects for ultra-large scale integration (ULSI) circuitry. One of the factors controlling film texture is the roughness of the deposition surface. In this paper the effects of dielectric roughness on the crystallographic texture of physical vapor deposited (PVD) copper seed layers and, subsequently, on the texture of electroplated (EP) copper have been investigated. Six relevant interlevel dielectric materials were examined: tetraethyloorthosilicate (TEOS), borophosphosilicate glass (BPSG), silane oxide, silicon nitride, SiLKTM (from the Dow Chemical Corporation), and polysilicon were deposited on 200 mm (001) Si wafers. The RMS surface roughness of these dielectric layers, measured by AFM, ranged from 0.32 nm to 20.51 nm. Texture was analyzed on a dedicated x-ray diffractometer equipped with a two dimensional detector collecting incomplete pole figures with a 1.0 degree resolution in pole figure space. The orientation distribution functions (ODF) were calculated using the arbitrary defined cells method and the volume fractions of major fiber texture components were derived from the ODF. The predominant texture components of the PVD and EP copper were (111) and (511) fiber. It was found that the volume fraction of (111) fiber decreased as the dielectric surface roughness increased. One exception was with the SiLKTM dielectric, which produced significantly weaker texture than other dielectrics with similar surface roughness. The copper films deposited on polysilicon, which possessed the roughest deposition surface of all the dielectric films had a random texture. Finally, a mixture of strong (111) and (511) fiber textures of EP copper was achieved on dielectric underlayers with smoother surfaces. The results demonstrate that the deposition surface roughness plays an important role in establishing the texture in overlying PVD and EP Cu films. The texture of PVD and EP copper may serve as a useful indicator of the underlayer roughness.

Three-dimensional texture determination of 6111 aluminium alloy sheet by precise serial sectioning and EBSD measurement

A method of accurate serial sectioning has been designed for three-dimensional texture measurement in aluminium alloy sheet. Using this method, determination of three dimensional texture in an AA6111-T4P sheet has been carried out by electron backscatter diffraction (EBSD) in a scanning electron microscope (SEM) from the sheet surface to 1/3 of the thickness. Optimal conditions for specimen preparation and SEM operation have been investigated to ensure minimum planar displacement or rotation among sections. It has been demonstrated that in the AA6111-T4P sheet the {001}〈100〉 (cube), {011}〈100〉 (Goss) and {011}〈455〉 (P*) orientations are the major texture components. The through thickness averaged cube and Goss components are aligned parallel to the rolling direction forming a banded structure, and the bands of the cube and Goss are distributed alternately in the transverse direction. The variation in grain size is very limited compared with the texture components.

EBSD study of the orientation dependence of substructure characteristics in a model Fe−30wt%Ni alloy subjected to hot deformation

The aim of the present investigation was to determine the orientation dependence of substructure characteristics in an austenitic Fe-30wt%Ni model alloy subjected to hot plane strain compression. Deformation was carried out at a temperature of 950 degrees C using a strain rate of 10 s(-1) to equivalent strain levels of approximately 0.2, 0.4, 0.6 and 0.8. The specimens obtained were analysed using a fully automatic electron backscatter diffraction technique. The crystallographic texture was characterized for all the strain levels studied and the subgrain structure was quantified in detail at a strain of 0.4. The substructure characteristics displayed pronounced orientation dependence. The major texture components, namely the copper, S, brass, Goss and rotated Goss, generally contained one or two prominent families of parallel larger-angle extended subboundaries, the traces of which on the longitudinal viewing plane appeared systematically aligned along the {111} slip plane traces, bounding long microbands subdivided into slightly elongated subgrains by short lower-angle transverse subboundaries. Relatively rare cube-orientated grains displayed pronounced subdivision into coarse deformation bands containing large, low-misorientated subgrains. The misorientation vectors across subboundaries largely showed a tendency to cluster around the sample transverse direction. Apart from the rotated Goss texture component, the stored energy levels for the remaining components were principally consistent with the corresponding Taylor factor values.

Texture Development during Grain Growth in Nonoriented Electrical Steels

Nonoriented electrical steels should have both low core loss and high permeability. These magnetic properties are largely affected by grain size and texture. The research on grain size optimization during grain growth has been very extensive whereas little attention has been paid to texture transformation during grain growth. In the present study, based on obtained experimental results, a mechanism of texture development during grain growth in nonoriented electrical steels is proposed. In the 2% Si specimens, the major texture components, Goss and {111}‹112› components, are weakened during grain growth. In the 1% Si specimens, the main texture components, {111}‹112› and {111}‹110›, are strengthened. It is proposed that for a texture component to be continuously strengthened during grain growth, the grains of the specific orientation should have not only a size advantage over those of other orientations, but also a higher frequency of high angle, high energy grain boundaries.

Effect of strain rate on deformation texture in OFHC copper

A strong strain rate dependence on the crystallographic texture of oxygen-free high conductivity copper is observed and reported for the first time. Two shear compression specimens were deformed at widely different strain rates (0.001 s � 1 and 7000 s � 1 ) to the same strain, and their textures were determined using orientation image microscopy. By comparing the stress–strain curves and the major texture components at the two strain rate levels, it is realized that increase in strain rate causes increase in strain hardening which thereby influences the texture. � 2004 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Texture evolution and mechanical anisotropy in dual-phase Ti3Al-based alloy loaded at 700 °C to 1000 °C

The super α 2 Ti3Al-based alloy with a fine grain size of ∼2.2 µm exhibits superplastic elongations over 1000 pct at 920 °C to 1000 °C, 600 pct at 900 °C, 330 pct at 850 °C, and 140 pct at 750 °C. Mechanical anisotropy is observed in this alloy, and relatively lower flow stresses and higher tensile elongations are obtained in the 45 deg specimen loaded at 25 °C to 960 °C. The texture characteristics appear to impose significant influence on the mechanical anisotropy at temperatures below 900 °C (under the dislocation creep condition), and the {111}〈2 % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9vqpe0x% c9q8qqaqFn0dXdir-xcvk9pIe9q8qqaq-dir-f0-yqaqVe0xe9Fve9% Fve9qapdbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGabGymayaara% GabGymayaaraaaaa!3AC4! $$\bar 1\bar 1$$ 〉 and {0001} basal textures evolve in the β and α 2 phases after tensile straining. At loading temperatures higher than 900 °C (under the superplastic flow condition), the anisotropy effect is less pronounced and the grain orientation distribution becomes basically random in nature. Rationalizations for the mechanical anisotropy in terms of the Schmid factor calculations for the major and minor texture components in the β and α 2 phases provide consistent explanations for the deformation behavior at lower temperatures as well as the initial straining stage at higher temperatures.

Effect of Niobium and Titanium on the Dynamic Recrystallization during Hot Deformation of Stabilized Ferritic Stainless Steels

The study was carried out to understand the mechanisms occurring during dynamic recrystallization of hot deformed 11% chromium stabilized ferritic stainless steels and to compare the behaviour induced by various types of stabilization. It was observed that continuous dynamic recrystallization (CDRX) operates in all materials starting at the onset of straining. Niobium has a more pronounced influence on hardening than titanium during hot deformation, which is due to solid solution strengthening and also to the reduction or stopping of grain boundary migration by solute drag effect. The D2 component, { 2 1 1 }<111>, was found as the major texture component at the steady state for the torsion tests carried along the negative shear direction. It was likely to be formed by the combination of straining and growth of the grains exhibiting both low stored energy and low rotation rate of the crystallographic axes.

Mechanical Anisotropy of Superplastic Ti<sub>3</sub>Al Based Alloy

The mechanical anisotropy in super α2 Ti3Al based alloys during low temperature superplasticity are explored. The alloy contains DO19 hexagonal α2 grains ~2.2 μm in grain size uniformly distributed in the ordered BCC β matrix. Although the alloy exhibits superior superplastic elongations over 1000% at 920-1000 o C, the elongation drops appreciably to 600% at 900 o C, 380% at 850 o C and 150% at 750 o C. Mechanical anisotropy is observed, and lower flow stresses and higher tensile elongations are obtained in the 45 o specimen as loaded at 25 to 960 o C. The texture characteristics appear to impose significant influence on the mechanical anisotropy at temperatures below 900 o C (under the dislocation creep condition). At loading temperatures higher than 900 o C (under the superplastic flow condition), the anisotropy effect was less pronounced and the grain orientation distribution become basically random in nature. Rationalizations for the mechanical anisotropy in terms of Schimid factor calculations for the major and minor texture components in the α2 and β phases provide consistent explanations for the deformation behavior at lower temperatures as well as the initial straining stage at higher temperatures.

On the Influence of the Misorientation of Grains, Grain Size and Boundary Volume on the Strength and Ductility of Ultrafine Grained Cu

AbstractThe influence of the microstructure and the misorientation relationship of grains on mechanical properties is investigated in specimens of ultrafine-grained copper processed by equal channel angular extrusion (ECAE) route Bc for 1, 4 and 12 passes. XRD texture analyses have shown that the major texture component is developed during the first pass of ECAE, and remains approximately constant with greater number of passes. EBSD measurements indicate that the majority of grain boundaries are still of low angle (>15°), while after four and twelve passes more than 50 % of all boundaries are high angle ones. TEM analyses have shown that the microstructure evolves from microbands and elongated cells towards a more equiaxed homogenous microstructure. On the microscale observed by TEM the degree of misorientation among subgrains/cells increases and the width of boundaries decreases while the cell/subgrain size remains approximately constant as the number of passes increases. The mechanical properties show a saturation level with a maximum in the yield stress and UTS after 4 passes. The strength of the material decreases between the fourth and the twelfth passes and the uniform elongation increases. It is suggested that the increase in ductility (and decrease in strength) is associated with the decrease in width of boundaries leading to an increase in the mean free path of dislocations.