bluuebunny/crossref_metadata_2025 huggingface dataset:
An Investigation of Microtexture Evolution in an AlMgSi Alloy Processed by High-Pressure Torsion
Authors: Loucif Aicha , Baudin Thierry , Brisset François , Figueiredo Roberto B. , Chemam Rafik , Langdon Terence G.
Published: December 2011

This investigation uses electron backscatter diffraction (EBSD) to study the development of microtexture with increasing deformation in an AlMgSi alloy having an initial grain size of about 150 µm subjected to high pressure torsion (HPT) up to a total of 5 turns. An homogeneous microstructure was achieved throughout the disc sample at high strains with the formation of ultra-fine grains. Observations based on orientation distribution function (ODF) calculation reveals the presence of the torsion texture components often reported in the literature for f.c.c. materials. In particular, the C {001}<110> component was found to be dominant. Furthermore, no significant change in the texture sharpness was observed by increasing the strain.
On the Orientation of Cell Block Boundaries in the Grains of a Rolled F.C.C. Polycrystal
Authors: Mahesh Sivasambu
Published: December 2011

Grains in f.c.c. polycrystals that accommodate imposed deformation purely byslip processes develop a multi-scale dislocation substructure that evolves with deformation.When the polycrystal is subjected to rolling deformation or to channel-die compression, oneof the elements of this substructure, called cell block boundaries, are widely reported to alignparallel to the transverse direction and close to the macroscopic plane of maximum shear. Thisobservation is explained based on standard rate-independent crystal plasticity augmented bythree hypotheses.
A Rate-Independent 'Stack' Model of a Polycrystalline Aggregate
Authors: Kumar M. Arul , Mahesh Sivasambu , Venkitanarayanan P.
Published: December 2011

The 'stack' model of a rate-independent rigid-plastic polycrystalline material is developed. In the 'stack' model, stacks of N neighboring sub-grain domains collectively accommodate the imposed macroscopic deformation while enforcing the velocity and traction continuity condition with its neighbors. The developed 'stack' model is applied to simulate the two-dimensional polycrystalline aggregate under macroscopically imposed plane-strain tension. The effect of inter- and intra-grain interactions on qualitative and quantitative variations in the predicted macroscopic stress-strain response and texture evolution are presented. The diminishing trend of constraint on individual sub-grain domains and texturing rate with stack size N, and saturation for large N also given.
Modeling of Deformation Microstructure - Strain Hardening and Crystallographic Reorientation of Crystallites in a Columnar Polycrystal
Authors: Alankar Alankar , Field David
Published: December 2011

In this work microstructure evolution in a columnar polycrystal of pure aluminum is studied using a microstructure sensitive crystal plasticity finite element model (CPFEM). In the model, based upon the kinematics of crystal deformation and dislocation interaction laws, dislocation generation and annihilation are modeled. Dislocation densities evolve in the form of closed loops and are tracked as state variables, leading to spatially inhomogeneous dislocation densities that show patterning in the dislocation structures. The hardening law is based on the strength of junctions between dislocations on specific slip systems. The CPFEM model is able to show the anisotropic hardening behavior of aluminum single crystals. The measures of accumulated plastic strain in the experiment and the simulation are compared with varying degrees of success.
Microstructural Modeling of Banding in Single Crystals: 'Stack of Domains' Model
Authors: Kumar M. Arul
Published: December 2011

A rigid-plastic rate-independent crystal plasticity based `stack of domains' model of a single crystal is developed to capture local deformation inhomogeneity and sub-structure formation when subjected to macroscopically homogeneous imposed deformation. This model regards the single crystal as a linear stack of domains with planar shaped domain boundaries. The domains of the model single crystal collectively accommodate the imposed deformation and individual domains maintain velocity and traction continuity with its neighbors. The lattice orientation of individual domains perturbed and that perturbation triggers the inhomogeneity of plastic slip amongst domains. Mobility of domain boundaries relative to the material and a differential hardening law that accounts for the orientational instability of individual domains are also considered in the model. The developed model is applied to predict the formation of banding in initially copper (C), rotated cube (RC) and Goss (G) orientated single crystals when subjected to plane strain deformation and the predictions are compared with the experimental literature.
Crystal Plasticity Predictions of Forward-Reverse Simple Shear Flow Stress
Authors: Jeong Young Ung , Barlat Frédéric , Lee Myoung Gyu
Published: December 2011

The flow stress behavior of a bake-hardenable steel during a few simple shear cycles is investigated using a crystal plasticity model. The simple shear test provides a stable way to reverse the loading direction. Stress reversals were accompanied with a lower yield stress, i.e., the Bauschinger effect, followed by a transient hardening stage with a plateau region and, permanent softening. The origins of these three distinct stages are discussed using a crystal plasticity model. To this end, the representative discrete grain set is tuned to capture such behavior by coupling slip system hardening appropriately. The simulated results are compared with experimental forward-reverse simple shear stress-strain curves. It is shown that the characteristic flow stress stages are linked to texture evolution and to the Bauschinger effect acting on the different slip systems.
Characterization and Modeling of Twinning in a Titanium Alloy Ti-6Al-4V
Authors: Coghe Frederik , Tirry Wim , Rabet Luc , van Houtte Paul
Published: December 2011

The twinning behavior of a commercial Ti-6Al-4V alloy is studied using a combined experimental and numerical approach. An extensive microstructural investigation was performed to identify and quantify the active twin systems. The mechanical behavior as a function of initial texture and strain rate was then modeled using a visco-plastic self-consistent crystal plasticity code (VPSC7). Earlier obtained quasi-static and dynamic data served to fit the parameters of the model, giving good agreement. However, even if the model gave qualitatively good predictions of the stress-strain curves and the texture evolution for the different loadings, the calculated twin fractions differed considerably of the experimental results.
On the Use of EBSD to Study the Heterogeneity of Plastic Deformation
Authors: Wagner Francis , Allain-Bonasso Nathalie , Berbenni Stephane , Field David P.
Published: December 2011

This paper deals with the study of plastic heterogeneity. It aims to study the role of both grain size and orientation distributions in the development of such heterogeneity. The considered material is an IF steel. EBSD maps have been made on the same areas before and after several degrees of extension. Parameters such as GOS (Grain Orientation Spread) or GOS/D (D the diameter of the grain) or GND (Geometrically Necessary Dislocation) densities have been determined for the whole set of grains as well as for subpopulations (smallest grains, largest grains for example). It appears that the character of neighboring grains plays a more important role than any of these parameters alone.
On the Role of Local Grain Interactions on Twin Nucleation and Texture Evolution in Hexagonal Materials
Authors: Kanjarla Anand K. , Beyerlein Irene J. , Lebensohn Ricardo A. , Tomé Carlos
Published: December 2011

Texture evolution in plastically deformed HCP metals is strongly influenced by the nucleation and growth of deformation twins and twin variant selection. Statistically based EBSD analyses of deformed microstructures in HCP metals indicate that the nucleation of deformation twins depends on, among other factors, the local stress fields arising from neighboring grain interactions at grain boundaries [1]. Inspired by these findings a probability model for twin nucleation was developed [2,3], based on the activation of defect sources statistically occurring in grain boundaries. This nucleation model was implemented in a Visco-Plastic Self-Consistent (VPSC) code. Because the latter is based on an Effective Medium assumption and the inclusion formalism, it only provides average stress values in the grains, and the nature of local stress fields at grain boundaries had to be considered in a heuristic manner. In order to have better insight on the effect of local textures on twin nucleation, in this work we employ a viscoplastic full field Fast Fourier Transform (FFT) method as a numerical tool for conducting virtual experiments to study the role of crystal orientation and local neighbor grain interactions on stress localization close to the interfaces and, consequently, on twin nucleation in hexagonal materials, such as Zr and Mg.
Grain Orientation Spread Values in if Steels after Plastic Deformation and Recrystallization
Authors: Ayad Abdelhak , Allain-Bonasso Nathalie , Rouag Nadjet , Wagner Francis
Published: December 2011

From an EBSD map made on a polycrystal one can define a set of grains using a criterion of misorientation between the adjacent pixels. Once such a list of grains is obtained, various quantities can be associated to each grain such as its size, (mean) orientation, GOS (Grain Orientation Spread) etc... The GOS associated to one grain is the mean value of the misorientations between all the pixels of the grain and the mean orientation of the grain. This value is quite sensitive to the state of the material (degree of plastic deformation, degree of recrystallization for example). Therefore it can help in interpreting the evolution of a microstructure during thermomechanical treatments. It is the purpose of this presentation to provide GOS values for an IF steel after several degrees of plastic deformation as well as after several annealing treatments which lead to partially or totally recrystallized states. The sources of influence on GOS values (as grain detection limit or grain size) are analyzed. The link between the values and the state of the material will be discussed at a global stage for a given population of grains.
Mechanical Property Anisotropy of 7010 Aluminum Alloy Sheet Having Single Rotated-Brass Texture
Authors: Mondal Chandan , Singh Ashok Kumar , Mukhopadhyay A.K. , Chattopadhyay K.
Published: December 2011

Mechanical property anisotropy in terms of in-plane anisotropy (AIP) of yield strength, and work hardening behavior of a heat treated 7010 aluminum alloy sheet has been investigated. The specimens were given two different types of heat treatments that result in a unique single rotated Brass-{110}á556ñ component with different texture intensity and volume fraction of recrystallization. It has been observed that the AIP increases with increase in texture intensity and volume fraction of recrystallization. The results are discussed on the basis of Schmid factor analyses in conjunction with microstructural features namely, grain morphology and precipitation. On the other hand, work hardening behavior appears to be significantly affected by the microstructural features rather than type of texture present in the samples.
Nucleation of Recrystallization in Fine Grained AA3104 Alloy Analyzed by SEM and TEM Orientation Mappings
Authors: Paul Henryk , Morawiec Adam , Brisset François , Baudin Thierry
Published: December 2011

This paper describes nucleation and grain coarsening at very early stages of recrystallization in AA3104 aluminum alloy containing complex structure of second phase particles. Measurements of individual sub-cell orientations in ECAP-processed and slightly annealed structures were possible by using TEM-based orientation mapping in combination with recrystallization carried out in the microscope. The results were compared with those obtained by SEM/EBSD system. The investigation shows that the 40o<111>-type relation occurs rarely, and the rotation axes of misorientations between deformed and recrystallized areas were strongly scattered. Grouping of the misorientation axes near the <012>, <221>, <112> and <110> crystallographic directions was noticeable.
Mechanical Property Anisotropy of α (CPH) and α″ (Orthorhombic) Phases in Binary Ti-Nb Alloys
Authors: Banumathy S. , Mandal Rajiv Kumar , Singh A.K.
Published: December 2011

The present work describes the study of mechanical properties anisotropy of two binary alloys namely, Ti-8Nb and Ti-12Nb in hot rolled condition. These alloys were unidirectionally hot rolled to 80 % reduction at 800 °C and subsequently air cooled. The alloys Ti-8Nb and Ti-12Nb consist of mainly α and α″ phases, respectively and small volume fractions of β phase in hot rolled condition. Both the alloys exhibit non-basal main texture components. The ODF plots display weak, continuous and inhomogeneous [0001]||ND and [001]||ND fibres for the alloys Ti-8Nb and Ti-12Nb, respectively. In plane anisotropy (AIP) and anisotropy index (δ) were calculated from tensile results. Finally, an attempt has been made to correlate in plane anisotropy and yield locus to that of texture present in the hot rolled materials.
Texture Changes of Asymmetrically Rolled AA 1050 Al Alloy Sheets
Authors: Lee Jin Hyuk , Kim In Soo
Published: December 2011

Texture of Al alloy is affected to the formability and mechanical properties. In this paper, it was studied that the change of texture and formability of AA 1050 Al alloy sheets which were asymmetrically rolled. Asymmetrically rolled Al sheets showed that the distorted rotated cube texture, {001}, γ-fiber, ND// and {120} and {120} components were increased. The change of texture components after the asymmetrical rolling could be affected to the variation of plastic strain ratios of the asymmetrically rolled AA 1050 Al alloy sheets.
Key Microstructural Changes during High Strain Rate Superplastic Deformaion of an Al-Zn-Mg-Cu-Zr Alloy Containing Sc
Authors: Mukhopadhyay A.K. , Kumar A. , Prasad K.S. , Raveendra S. , Samajdar Indradev
Published: December 2011

The changes in texture and microstructure that occur during superplastic deformation (SPD) of a suitably thermo-mechanically processed (TMP) Al alloy AA7010 containing Sc at a temperature and strain rate combination of 475°C, 1.9x10-2s-1 have been examined. It is observed that during the early stages of SPD, there is a significant increase in the Brass {110}<112> component as well as a considerable increase in the S {123}<634> component. Whilst, these components gradually decrease leading to the randomization of texture as the SPD process progresses to larger strains. These results are discussed in terms of the nature of the TMP together with significant variations in the number density of Al3ScxZr1-x dispersoids and percentage recrystallization with strain.
Microstructural Evolution During Superplastic Forming of Al-Li 8090 Alloy
Authors: Pancholi Vivek , Kashyap B.P.
Published: December 2011

Commercial grade AA8090 Al–Li alloy sheet contained three layers of distinct microstructural features along thickness direction. The surface layer contained well recrystallized equiaxed grains with higher fraction of T {4 4 11}, Cu {1 1 2}, H {0 0 1} and CH {0 0 1} texture components whereas middle layer contained unrecrystallized elongated grains with higher fraction of brass {0 1 1}, CG {0 2 1} and goss{0 1 1} texture components. Superplastic forming of the separated surface and middle layers was carried out at constant pressure. Microstructure and texture evolution was studied at different location of the formed bulge. The extent of texturing or anisotropy was calculated from standard deviation of texture estimated normal anisotropy (R) values, Rstdev. At all conditions, in both the surface and middle layers, the texture randomization was found to be more at the apex than that at the edge of the bulge. The overall reduction in texturing was predominantly accompanied by weakening in strong texture components and strengthening in the weaker ones.
Formation and Development of Strong Cube Recrystallization Texture in an Aluminium of Commercial Purity
Authors: Helbert Anne Laure , Wang Wei , Baudin Thierry , Brisset François , Penelle Brisset
Published: December 2011

The goal of the present study inspired by previous works on high purity aluminiun was to manufacture aluminium sheets of commercial purity, grade 1050, with a strong cube texture. In this preliminary work on AA1050, sheets which cube volume fraction reaches 65% have been manufactured. Parameters controlling cube orientation development are mainly the solute dragging due to impurities in solid solution and the stored deformation energy. Besides the 85% cold rolling (CR), two extra annealings and a slight cold rolling are introduced in the processing route to increase the cube volume fraction. The cube orientation, whose substructure is equiaxed, is important for its recovery. It develops thanks to the difference of stored energy relative to that of its first neighbors; the slight cold rolling enhances growth of these cube grains.
On the Impact of Thermo-Mechanical Processing on Texture and the Resultant Anisotropy of Aluminium Sheet
Authors: Engler Olaf
Published: December 2011

During the thermo-mechanical processing of aluminium sheet products in commercial production lines the material experiences a complex history of temperature, time and strain paths, which result in alternating cycles of deformation and recrystallization with the associated changes in microstructure and, especially, crystallographic texture. Thus, computer-based alloy and process development requires integration of models for simulat¬ing the evolution of microstructure, microchemistry and crystallographic texture into process models of the thermo-mechanical production of Al sheet. In the present paper the influence of texture on the anisotropic properties is explored for various industrially processed aluminium alloy sheets for packaging applications. Besides the use of experimentally measured sheet textures as an input for the anisotropy calculations, particular attention is given to the use of modelled textures. Here, results from a comprehensive through-process modelling of the texture evolution during the thermo-mechanical production of aluminium sheet are utilized. Eventually, this will enable us to predict the evolution of texture and the resulting properties along the entire process chain and hence to improve product quality of aluminium sheet products avoiding laborious and expensive plant trials.
Effect of Hot-Deformation on Micro-Texture in Ultra-Fine Grained HSLA Steel
Authors: Patra S. , Kumar Vinod , Haldar Arunansu , Chakrabarti Debalay
Published: December 2011

Plane-strain compression testing on HSLA steel samples using single-pass and multi-pass hot-deformation schedules showed that heavy deformation of metastable austenite below Ae3, developed ultra-fine ferrite grains (<3 µm), increased the fraction of high-angle (>15º misorientation) boundaries (>70%), and encouraged the formation of beneficial g-fibre ((ND//<111>) components along with {332}<113> and {554}<225> texture components, minimising the intensity of harmful ‘cube’ texture.
Texture and Microstructure of WE54 Alloy after Hot Rolling and Annealing
Authors: Azzeddine Hiba , Bradai Djamel
Published: December 2011

The texture and microstructure after hot rolling and annealing of WE54 alloy was investigated using X-ray techniques and optical microscopy. WE54 alloy was hot rolled at 400°C to two different reductions (20% and 53%) and then annealed at 450°C for 30 minutes. These treatments resulted in a retained but much weaker basal texture with grain size almost unchanged.
Investigation of Texture Gradients of Semi-Finished Products by Neutrons and Photons
Authors: Brokmeier Heinz Guenter , Randau Christian , Gan Wei Min , Hofmann Michael , Lippmann Thomas , Schell Norbert
Published: December 2011

Texture gradients are present in most samples, which are due to materials processing. Standard methods to evaluate texture gradients are based on the cut of samples, such as the X-ray investigation of surface textures against the texture inside a sheet. Bulk textures itself averaging over the whole sheet thickness are analysed by thermal neutrons. Both thermal neutrons and photons with high energies allow investigations non-destructively. The beam port Stress-Spec at the Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II) at Garching/Germany is equipped with a robot system based on a RX160 Stäubli robot, a Laser Tracker and a heavy basement. Samples up to 30kg can be investigated. Main restrictions are the available neutron flux, the detector efficiency and the detector size. Thus, the gauge volume is restricted to 1x1x1mm for ideal scattering conditions to measure in acceptable time scale. Photons with up to 200keV are known as high brilliant and high intense beam with similar penetration power than thermal neutrons. A typical set up of a high energy beamline for texture gradient investigations works without an Eulerian cradle so that restrictions in handling large sample are of less importance. The HZG materials science beamlines at Doris III and Petra III (Harwi-II@DorisIII and HEMS@PetraIII) are equipped with massif units for sample rotation and x-, y- and z- scanning for samples and additional equipments up to 200kg. Compared to thermal neutrons, which work with wavelengths between 1Å-2.5Å, the wavelength of high energy photons is small (0.05Å – 0.20Å). That leads on one hand to low scattering angles (1° - 10°) and on the other hand to an anisotropic ellipsoidal gauge volume. The local resolution of the synchrotron beam is much better than for thermal neutrons. In both methods corrections for constant gauge volume during pole figure scanning and for anisotropic absorption are of great importance.
Quantifying Damage Accumulation Using State-of-the-Art FFT Method
Authors: Pokharel Reeju , Li S. F. , Lind J. , Hefferan C. M. , Lienert U. , Lebensohn R. A. , Suter R.M. , Rollett A.D.
Published: December 2011

A 3D microstructure, measured by high-energy x-ray diffraction microscopy, is used as an input to a parallelized viscoplastic Fast Fourier Transform code (VPFFT) to simulate a tensile test. Distributions of strain, damage accumulation, neighbor interactions, and Schmid factor mismatch throughout the microstructure are calculated. These results will form the basis of a direct comparison to microstructure maps that track plastic deformation in the real sample.
Study of Deformation Twinning and Planar Slip in a TWIP Steel by Electron Channeling Contrast Imaging in a SEM
Authors: Gutierrez-Urrutia Ivan , Raabe Dierk
Published: December 2011

We study the dislocation and twin substructures in a high manganese twinning-induced-plasticity steel (TWIP) by means of electron channeling contrast imaging. At low strain (true strain below 0.1) the dislocation substructure shows strong orientation dependence. It consists of dislocation cells and planar dislocation arrangements. This dislocation substructure is replaced by a complex dislocation/twin substructure at high strain (true strain of 0.3-0.4). The twin substructure also shows strong orientation dependence. We identify three types of dislocation/twin substructures. Two of these substructures, those which are highly favorable or unfavorable oriented for twinning, exhibit a Schmid behavior. The other twin substructure does not fulfill Schmid’s law.
High Resolution Orientation Distribution Function
Authors: Schmidt Søren , Gade-Nielsen Nicolai Fog , Høstergaard Martin , Dammann Bernd , Kazantsev Ivan G.
Published: December 2011

A new method for reconstructing a High Resolution Orientation Distribution Function (HRODF) from X-ray diffraction data is presented. It is shown that the method is capable of accommodating very localized features, e.g. sharp peaks from recrystallized grains on a background of a texture component from the deformed material. The underlying mathematical formalism supports all crystallographic space groups and reduces the problem to solving a (large) set of linear equations. An implementation on multi-core CPUs and Graphical Processing Units (GPUs) is discussed along with an example on simulated data.
Virtual 3D Microstructures with Specified Characteristics of State Variable Distributions
Authors: Gomes Edgar , Verbeken Kim , Kestens Leo A.I.
Published: December 2011

For a wide variety of model calculations a hypothetical 3D microstructure is required as input. Although experimental data are frequently used to this purpose, 3D microstructures are difficult to measure experimentally. In order to circumvent these difficulties, a virtual microstructure generator to simulate a specific 3D material microstructure is proposed. Such a virtual microstructure could serve as input for different types of models, would allow a faster model prototyping, would help to explore the boundary conditions of models and reduces the number of unnecessary experimental measurements. In the current paper, the method to generate and to control the grain size distribution as well as texture are discussed.
The Effect of Cold Rolling Direction on the Secondary Recrystallization in Fe-3%Si Steel
Authors: Ko Kyung Jun , Park Hyung Ki , Han Chan Hee
Published: December 2011

In order to verify the origin of Goss nuclei for secondary recrystallization in Fe-3%Si steel, the effect of cold-rolling direction on the secondary recrystallization was examined in this study. The cold-rolling direction was rotated through 0 ~ 90 degrees about the hot-rolling direction on normal direction axis of hot-rolled sheet. In spite of the different initial texture before cold rolling, the 88% cold rolled texture was formed by similar α and γ fiber regardless of the rotation of cold rolling direction. Likewise, regardless of the cold rolling direction, the primary recrystallized sheets had a similar texture. In particular, the area fraction of Goss component (tolerance angle within 15º) in the primary recrystallized sheets was increased in the cold rolling condition of rotating through 60, 90 degrees from the hot rolling direction. After high temperature annealing at 1200°C, the secondary recrystallized grain was fully evolved in the all conditions. The sharpness of Goss texture in secondary recrystallized sheet was decreased as increasing the rotation angle of cold rolling direction.
Modeling of the Particles Pinning Effect on Grain Growth
Authors: Maazi N. , Penelle R.
Published: December 2011

In silicon steels, interaction of grain boundaries with particles occurs in a selective way. Currently, it is very difficult to include this preferential interaction directly in the classical simulation models. A new approach of grain growth simulation based on the concept of curvature-driven migration of the grain boundaries in the presence of particles has been used to study the abnormal grain growth (AGG) in Fe-3%Si alloy.
Grain Boundary Migration and Grain Growth Texture Evolution in Zn in a High Magnetic Field
Authors: Günster Christoph , Molodov Dmitri A. , Gottstein Günter
Published: December 2011

The magnetically driven motion of planar symmetrical and asymmetrical <> tilt grain boundaries in high purity (99,995%) zinc bicrystals was measured in-situ by means of a po­la­rization microscopy probe in the temperature range between 330°C and 415°C and the corres­pon­ding migration activation parameters were obtained. The results revealed that grain boundary mobi­lity essentially depends on the misorientation angle and the inclination of the boundary plane. The magnetic annealing of the cold rolled (90%) Zn-1.1%Al sheet specimens resulted in an asymmetry of the two major texture components. This effect is attributed to a magnetic driving force for grain growth. The grain microstructure evolution was also essentially affected by a magnetic field.
Compromising Effect on Development of Recrystallization Texture in Aluminium Sheet – A 2D MC Type Simulation –
Authors: Ito Kunio
Published: December 2011

The migration rates of C->Si, Si->C, and Si->Sj were assumed to be high and those of Si->Si and all other rates to be low. Here Si(i=1,2,3,4) is a variant of S orientation and C->Si means the growth of a cube grain into an Si grain. The textural development through grain coarsening was simulated as a function of the ratio of the high rate to the low one. The compromising effect surely promotes the development of the cube texture but its decisive development requires any asymmetry between C->Si and Si->C migration processes.
Texture Control of Aluminum and Magnesium Alloys by the Symmetric/Asymmetric Combination Rolling Process
Authors: Inoue Hirofumi
Published: December 2011

In order to develop favorable textures for deep drawing of Al-Mg-Si and Mg-Al-Zn alloys that are promising as automotive body panels, we have adopted the symmetric/asymmetric combination rolling (SACR) process consisting of conventional symmetric rolling and subsequent asymmetric rolling at relatively low reduction. The combination of symmetric cold rolling and asymmetric warm rolling for AA6022 sheets leads to the formation of “TD-rotated β-fiber texture”, resulting in the evolution of {111} recrystallization texture after solution treatment at a high temperature. The SACR processed and solution-treated sheets show a high average r-value with small in-plane anisotropy, and consequently the limiting drawing ratio increases significantly, compared to that of the cold-rolled and solution-treated sheets. In the case of AZ31 magnesium alloy, the SACR process by hot rolling causes the formation of a unique texture, which shows two (0001) poles with tilt angles of 0 and −40 degrees from the normal direction (ND) toward the rolling direction (RD). In addition, subsequent annealing weakens intensity of the double-peak texture, so that the drawability is greatly improved in comparison with that of the conventional warm-rolled sheets with a strong basal texture. At the same time, yield strength decreases to some extent, but the SACR processed and annealed sheets exhibit a good balance of strength and formability due to a mixed texture with basal and tilt components.
Recrystallization Textures of Cross-Rolled 3.3% Si Electrical Steel and 99.99% Copper Sheets
Authors: Lee Dong Nyung , Han Heung Nam , Choi Hyun Sik
Published: December 2011

The recrystallization (Rex) texture of cross-rolled 3.3% Si steel was similar to the deformation texture approximated by {100}. The deformation texture of cross-rolled 99.99% copper was approximated by major {110} plus minor {001}. Its Rex texture was approximated by major {110} plus minor {001}. The results have been discussed based on the strain-energy-release-maximization model.
Correlation between Texture at Primary Recrystallized State and Magnetic Properties in Grain Oriented Electrical Steels
Authors: Park Jong Tae , Joo Hyung Don , Song Dae Hyun , Ko Kyung Jun , Park No Jin
Published: December 2011

Desirable magnetic properties for grain oriented electrical steels are low core loss and high magnetic flux density. These properties are closely related with sharpness of {110} texture. This Goss texture develops by abnormal grain growth during secondary recrystallization annealing. Based on experimental results, a general suggestion which estimates the magnetic properties after completion of secondary recrystallization from a primary recrystallized texture can be proposed. For a material to have better magnetic properties after completion of secondary recrystallization, it should have a primary recrystallized texture in which there are not only large number of ideal Goss grains, but also lower frequency of low angle grain boundary around those Goss grains.
Microstructure and Texture Evolution in Interstitial-Free (IF) Steel Processed by Multi-Axial Forging
Authors: Bhowmik Ayan , Biswas Somjeet , Dhinwal Satyaveer Singh , Sarkar Apu , Ray Ranjit Kumar , Bhattacharjee Debashish , Suwas Satyam
Published: December 2011

In this study, severe plastic deformation (SPD) of Ti-bearing interstitial-free steel was carried out by multi-axial forging (MAF) technique. The grain refinement achieved was comparable to that by other SPD techniques. A considerable heterogeneity was observed in the microstructure and texture. Texture of multi-axially forged steels has been evaluated and reported for the first time. The material exhibited a six-fold increase in the yield strength after four cycles of MAF.
Improvement of Crystallographic Texture of High Strength Interstitial Free Steels by the Control of Steel Chemistry and Coiling Temperature
Authors: Bhattacharya Basudev
Published: December 2011

Effects of steel composition and coiling temperature on textures of a series of high strength IF steels were studied. An intermediate coiling temperature (6200C), instead of a high coiling temperature (7100C), was found most beneficial for the steels containing moderate to high phosphorus content. On the other hand, high coiling temperature was found beneficial for the steels containing low amount of phosphorus.
Recrystallization Texture of Ferrite Steels: Beyond the γ-Fibre
Authors: Gobernado Patricia , Petrov Roumen H. , Moerman Jaap , Barbatti Carla , Kestens Leo A.I.
Published: December 2011

The recrystallization texture of highly cold deformed IF steels is addressed. The latter is characterized by the //ND fibre and a certain spread towards the {311} orientation. The //ND fibre is the optimum texture for enhanced deep-drawing properties whereas the presence of any other component, such as {311}, will deteriorate the plastic anisotropy of the material. Previous works concluded that the recrystallized {311} orientation results from an oriented nucleation process related to the plastic instability of {001} deformed grains. In the present work, the microstructural nature of such plastic instability is investigated by high resolution orientation scanning microscopy on an annealed IF sample after cross-rolling. Present data indicate that localized deformation in near {001} grains plays an essential role in the nucleation of {311} orientations.
Microstructure Evolution in Deformed Ultrahigh Carbon Low Alloy (Wootz) Steel
Authors: Kumar Vinod , Balasubramaniam R. , Kumar P.
Published: December 2011

The evolution of microstructure with degree of deformation in a deformed wedge shaped hypereutectoid steel implement, containing 1.84 C, 0.06 Si, 0.01 S, 0.14 P, 0.11 Cu, 0.017 Zr and 0.05 Ce, has been characterized using optical and scanning electron microscopy (SEM) and electron back scattered diffraction (EBSD). Microstructures consisted of bulky carbides dispersed in a matrix of pearlitic, with grain boundary proeutectoid cementite, side plate Widmanstatten cementite and intragranular cementite were noted in region of low strain. The cast structure was broken down with increasing degree of deformation. The mechanism for the formation of spheroidization of cementite in hypereutectoid steel has been proposed. Microstructural analysis of high strain region consists of fine equiaxed ferrite grains surrounded by high angle boundaries.
Orientation Relationships of Coarse Pearlite Islands Formed in Tundish Well Clogging Deposits
Authors: Triguero Patricia Romano , Zinngrebe Enno , Melzer Stefan
Published: December 2011

It is well known that clogging constitutes one of the main issues encountered during casting in the steel industry. To clarify how clogging deposits are formed and to minimize their impact in the process, their microstructure and relationship between the different constituents need to be studied. In the tundish well the studied deposits consist predominantly of Al2O3 inclusion fans but are found interspersed with islands of pearlite along the margins. These islands of coarse pearlite, i.e. thick cementite/ferrite plates surrounded by large ferrite grains are formed even in Ti-rich ultra low carbon steels and the orientation relationships are used to track the initial composition of the deposit when it was formed. The crystallographic orientation relationship (ORS) between ferrite and cementite in pearlite can follow Isaichev (I), Bagaryatskii (B) or Pitsch-Petch (PP). Results showed that the pearlite islands are formed with ORS relatively close to PP and are intersected by alumina particles which show a specific relation with the islands and with the ferrite matrix. It was concluded that an external carbon source and temperatures just above the eutectoid are needed to form those islands.
Study of Recrystallization and Phase Transformation in a Cold-Rolled Dual-Phase Steel: Influence of Temperature and Heating Rate during First Annealing Stages
Authors: Barbatti Carla , Triguero Patricia Romano , Van Bohemen Stefan , Celotto Steven , Hanlon Dave N.
Published: December 2011

The effect of heating path and heating rate on the microstructure and texture development in cold-rolled continuously annealed DP steel was studied by SEM and EBSD. A methodology to separate the individual phases present in mixed microstructures, and thus to enable quantification of the individual contributions to the bulk texture has been applied. It was observed that a higher heating rate may promote strengthening of {111} textures in DP steels as observed in low carbon grades.
Effects of Grain Size and Texture on the Biocompatibility of Commercially Pure Titanium
Authors: Hoseini Majid , Bocher Philippe , Azari Fereshteh , Vali Hojatollah , Szpunar Jerzy A.
Published: December 2011

Ultra fine grained (UFG) pure titanium fabricated by severe plastic deformation techniques has been recently considered for biomedical applications. In this study, the effects of grain size and crystallographic orientation on the biocompatibility of commercially pure titanium have been evaluated. Samples having significant differences in terms of average grain size (from 0.4 to 20 mm) and crystallographic textures have been produced using equal channel angular pressing (ECAP) and compared. X-ray diffraction and electron back scattered diffraction (EBSD) were used to document the texture and microstructural properties. Cell attachment tests were done to study the biocompatibility of the samples using MC3T3 pre-osteoblast cells. The number of attached cells was found to be higher on the samples having more (0002) plane parallel to the surface regardless of their grain sizes. It was concluded that the texture plays a more significant role than the grain size in the biocompatibility of pure titanium.
Plastic Deformation of Textured Zircaloy 2
Authors: Sahoo Santosh Kumar , Hiwarkar V. D. , Pant Prita , Samajdar Indradev , Mani Krishna Karri V. , Dey Gautam Kumar , Srivastava Dinesh , Tewari R. , Banerjee S.
Published: December 2011

The present study deals with deformation behaviour of textured Zircaloy 2 with two dominant orientations: basal and non-basal. During initial stages (20%), two distinct class of grains were observed – non-deforming/non-fragmenting grains and deforming/fragmenting grains. The so-called non- deforming/non-fragmenting grains remain equiaxed even after 50% of deformation. They also have insignificant in-grain misorientation developments and have more residual stresses. Dislocation dynamics simulation showed that the dislocation interactions/mobility is insignificant in basal orientations at room temperature deformations.
Texture Formation in α-Zr of Zr-1%Nb Alloy under Radial Forging
Authors: Perlovich Yuriy , Isaenkova Margarita , Fesenko Vladimir , Krymskaya Olga , Lenskiy Mikhail , Zavodchikov Alexander
Published: December 2011

Features of the deformation process by cold radial forging of tube billets from Zr-1%Nb alloy were reconstructed on the basis of X-ray texture data. The cold radial forging intensifies grain fragmentation in the bulk of billet and increases significantly the latent hardening of potentially active slip systems, so that operation only of the single slip system becomes possible. As a result, in radially-forged billets unusual deformation and recrystallization textures arise, differing from usual textures of a-Zr by the mutual inversion of crystallographic axes, aligned along the axis of tube.
Variant Selection and Texture in an AISI 301LN Stainless Steel
Authors: Marechal David , Malet Loic , Godet Stéphane , Sinclair Chad W.
Published: December 2011

There has recently been significant interest in the problem of variant selection in the strain-induced transformation of austenite to α’-martensite in metastable austenitic stainless steels. Previous work has highlighted our poor understanding of the mechanisms leading to this transformation, in particular the role that the macroscopic stress plays in the transformation. In this work, we have sought to perform detailed experiments aimed at developing a statistical grain level view of variant selection in one particular grade of austenitic stainless steel. EBSD measurements made over a large number of grains as well as macroscopic texture measurements made at different levels of imposed plastic strain allow for comparison against various approaches for predicting variant selection based on the Patel-Cohen interaction energy.
Nanocrystallization and Texture Transformation in the Surface Layer of Copper Induced by Surface Mechanical Attrition
Authors: Liu Gang , Wang Gang , Liu Y.D. , Wu B.L. , Zhao X. , Zuo L.
Published: December 2011

A nanostructured surface layer was synthesized in a pure copper plate by means of surface mechanical attrition (SMA). The evolutions of microstructure and orientation were examined by using XRD, TEM and ODF. The microstructural evolution with the treatment time can be divided into two stages: the first is characterized by a formation of nc grains with small to medium misorientations in the surface layer and a texture transformation from rolling type to shear one in the near-surface layer, and the second by a significant increment of misorientations between the nc grains and a texture transformation from shear type back to rolling one. It might be reasonably deduced that shear stress can effectively induce grain refinement, and the combination of shear and compress stresses might be helpful for the increment of grain boundary misorientations.
Evolution of Hot Rolling and Phase Transformation Textures in an α″ (Orthorhombic) Phase in Ti-Nb Alloys
Authors: Banumathy S. , Mandal Rajiv Kumar , Singh A.K.
Published: December 2011

This work describes the development of texture during hot rolling of two alloys namely, Ti-12Nb and Ti-16Nb. The alloys have been unidirectionally hot rolled to 80 % reductions at 800°C and air cooled. Both the alloys show the presence of a² (orthorhombic) and small volume fraction of b (bcc) phases in hot rolled condition. The alloy Ti-12Nb exhibit moderate intensity texture while the alloy Ti-16Nb displays quite strong texture. The high overall intensity of texture in alloy Ti-16Nb in 80 % HR specimen can be attributed to the presence of large volume fraction of b phase in comparison to that of the alloy Ti-12Nb. This has been extended to study the textural changes after b solution treatment. This heat treatment consists of two types of phase transformations that are a² ® b ® a² and a² ® b ® a after water quenching and furnace cooling from β phase field.
Evolution of Texture during Directional Solidification of Giant Magnetostrictive Tb0.3Dy0.7Fe1.95 Alloy
Authors: Palit Mithun , Chelvane J. Arout , Basumatary Himalay , Banumathy S. , Singh A.K. , Pandian S. , Chattopadhyay K.
Published: December 2011

The development of preferred grain orientation has been investigated in the directionally solidified samples of Tb0.3Dy0.7Fe1.95 as a function of pulling speed viz. 10, 40, 70 and 100 cm/h. The study indicates that at lower solidification rate (10 cm/h) growth of and texture components are preferred, whereas, texture component becomes dominant at higher pulling rate (100 cm/h). However, as the solidification progresses, growth of texture component is observed subduing the other components. Consequently, the magnetostriction improves from 1100 to 1350 micro-strains with higher pulling speed.
Restitution of Prior-Austenite Grain Orientation by Microtexture Analysis of Tempered Martensite Structure in 9Cr-1Mo Ferritic Steel
Authors: Dash Manmath Kumar , Karthikeyan T. , Saroja S. , Vijayalakshmi M.
Published: December 2011

The 9Cr-1Mo-0.1C steel was solutionzed (1323 K for 1hr) and step cooled (at 40 K/hr between Ms and Mf) to effect martensitic transformation at slower rates, and then subsequently tempered (1023 K for 2 hr). The microtexture of the tempered martensite structure was evaluated using SEM-Electron Back Scattered Diffraction (EBSD) technique, and the crystal orientation data of ferrite crystallites formed within a single prior-γ grain were analyzed in detail. The Kurdjumov-Sachs (K S) orientation relationship (111)γ // (011)α´ [-101]γ // [-1-11]α´ is commonly obeyed in low carbon steels, and a restitution methodology was used to back calculate the orientation of parent γ grain assuming the K-S relationship. The austenite was identified as the common solution of the data set, and its mean orientation has been calculated. The mean deviation from the K-S was calculated to be 3.75º.
An EBSD Study of Gallium Arsenide Nanopillars
Authors: Camus Patrick P. , Shapiro Joshua , Prikhodko Sergey V.
Published: December 2011

GaAs nanopillars show promise for energy applications. Understanding, characterizing and modifying the structure of the pillars will be very important for optimizing the properties of the assemblies. EBSD was used to investigate the orientations of these nanometer structures.
Investigation on Texture Evolution in Plastic Deformation Layer of SMAT Iron
Authors: Chen Wei Ye , Tong Wei Ping , He Chang Shu , Zhao Xiang , Zuo Liang
Published: December 2011

The texture evolution in the plastic deformation layer of the pure iron sample after the surface mechanical attrition treatment (SMAT) was discussed through electron backscattering and X-ray diffraction (XRD) analysis. The results showed that: the surface layer of the iron sample can be subdivided into four sub-layers along the depth from the top surface: nano-sized regime, submicro-sized regime, micro-sized regime and deformed coarse-grained regime. Nano-sized regime possesses random crystallographic orientations. But in submicro-sized regime and micro-sized regime, the //ND fiber texture is the prominent texture with a strong orientation of (110)[1-11]. Increasing treatment time during SMAT process does not change the components of texture in plastic deformation layer, only strengthen their orientation density.
Microstructure Evolution and Mechanical Behaviour of Severe Plastically Deformed Cu
Authors: Sharma Garima , Sarkar Apu , Samajdar Indradev , Chakravartty J.K.
Published: December 2011

The present study reports the microstructure evolution and mechanical behaviour of severe plastically deformed pure Cu under cryogenic conditions. The samples were severely deformed by cryo rolling upto 50%, 75% and 95% deformation. Microstructure evolution of cryo rolled samples has been characterized by using optical, TEM and EBSD technique. The rolled samples were heat treated at various temperatures so as to control the recrystallization in the severely deformed samples. The effect of recrystallization on the mechanical behaviour was investigated in detail by tensile testing. The EBSD analysis performed on 95% rolled + heat treated samples showed that partial recystallized microstructure demonstrate an optimum combination of strength and ductility in cryo rolled Cu.