bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Ultrahigh Straining on the Evolution of Cube Texture ({100}<100>) in High Purity Nickel
Authors: Bhattacharjee Pinaki Prasad , Tsuji Nobuhiro
Published: December 2011

The effect of ultrahigh straining on the evolution of cube texture in high purity nickel (99.97%) processed by Accumulative Roll Bonding (ARB) is investigated in the present study. Fully recrystallized nickel sheet having average grain size of 28 μm is deformed by ARB to the strain levels of εeq=3.2 and εeq=6.4 corresponding to 4 and 8 cycles of ARB processing, respectively, and subsequently annealed at different temperatures. The 8 cycle ARB processed material consistently shows much higher cube volume fraction as compared to the 4 cycle processed material after different annealing treatments. Almost 100% cube volume could be obtained in the 8 cycle processed material after annealing at 800°C. The development of extremely sharp cube texture in the 8 cycle processed material could be attributed to the oriented nucleation of cube grains at early stages of recrystallization and subsequent growth of these grains. The results indicate that ultrahigh straining could be useful for applications requiring near perfect cube texture such as substrates for coated superconductors applications.
The Application of 3D-EBSD for Investigating Texture Development in Metals and Alloys
Authors: Ferry Michael , Quadir M. Zakaria , Zinnia Nasima Afrin , Bassman Lori , George Cassandra , Mcmahon Cullen , Xu Wan Qiang , Laws Kevin J.
Published: December 2011

A focused ion beam (FIB) coupled with high resolution electron backscatter diffraction (EBSD) has emerged as a useful tool for generating crystallographic information in reasonably large volumes of microstructure. In principle, data generation is reasonably straightforward whereby the FIB is used as a high precision serial sectioning device for generating consecutive milled surfaces suitable for mapping by EBSD. However, there are several challenges facing the technique including the need for accurate reconstruction of the EBSD slice data and the development of methods for representing the myriad microstructural features of interest including, for example, orientation gradients arising from plastic deformation through to the structure of grains and their interfaces in both single-phase and multi-phase materials. This paper provides an overview of the use of 3D-EBSD in the study of texture development in alloys during deformation and annealing and includes an update on current research on the crystallographic nature of microbands in some body centred and face centred cubic alloys and the nucleation and growth of grains in an extra low carbon steel.
Dislocation Densities, Slip-System Types and Burgers Vector Populationsinhexagonal and Cubiccrystalsfrom X-Ray Line Profile Analysis
Authors: Ungár Tamás
Published: December 2011

X-ray diffraction line profile analysis can be carried out on the hkl planes corresponding to the same texture component or the same crystallographic orientation fiber. It is shown that in textured polycrystalline materials or in thin films or multilayers X-ray line profiles measured on planes corresponding either to the main or the minor texture components can provide the Burgers vector population and dislocations densities in the different texture components separately. The experimental technique is outlined for textured specimens and the multiple convolutional whole profile method, i.e. the CMWP line profile analysis procedure, is presented for its capacity to determine the substructure pertaining to different texture components in textured samples.
Deep Drawing of ZK60 Wrought Magnesium Alloys
Authors: Cho Jae Hyung , Jeong Sang Su , Kang Suk Bong
Published: December 2011

Evolution of texture and microstructure during deep drawing of ZK60 wrought magnesium alloys were investigated using EBSD (electron backscatter diffraction). ZK60 (Mg-5.5Zn-0.6Zr) alloys were prepared through both direct chill casting (DC) and twin-roll strip casting (TRC). Deep drawing tests were carried out under various working temperature and drawing speeds. The diameters of the sheets and punch were 74 mm and 37 mm, and overall limit drawing ratio was 2. Texture and microstructure evolution was examined with various working condition. The DC samples had larger grains than TRC samples, and thus more twins were observed in the DC samples.
Evaluation of Geometrically Necessary Dislocations Density (GNDD) near Phase Boundaries in Dual Phase Steels by Means of EBSD
Authors: Moerman Jaap , Triguero Patricia Romano , Tasan Cem , van Liempt Peter
Published: December 2011

The accumulation of dislocations around hard particles such as martensite in Dual Phase steel has a prominent influence on the mechanical properties of multiphase steels. The origin of these so-called Geometrically Necessary Dislocations (GNDs) is either due to the transformation strain, or to strain gradients that arise during deformation. The generation of deformation-GNDs is explained by Ashby’s theory [1] regarding deformation of a plastic mass that contains dispersed undeformable particles. It is argued that the GNDs pile up locally against the ferrite-martensite interface. This work reports the calculated density of GNDs from high resolution Electron BackScatter Diffraction (EBSD) measurements. By measuring the lattice orientation within the grains, the lattice curvature can be quan-tified, which can be directly related to the presence of GNDs. The density of the GNDs can then be estimated either directly through kernel average misorientations, or through the calculation of the dislo-cation tensor. From this first approximation of the GND density a GNDD map has been obtained by two recently developed approaches. This map shows an enhanced dislocation density around the mart-ensite particles due to volume change during transformation. The kernel choice and step size depend-ency of the results are also investigated.
Recent Advances in Texture Measurement Using Two-Dimensional Detector
Authors: He Bob B.
Published: December 2011

The two most important advances in two-dimensional x-ray diffraction (XRD2) are area detectors for collecting 2D diffraction patterns and algorithms in analyzing 2D diffraction patterns. The VÅNTEC-500 area detector represents the innovation in detector technology. The combination of its large active area, high sensitivity, high count rate, high resolution and low noise, makes it the technology of choice for many applications, including texture analysis. A 2D diffraction pattern contains information in a large solid angle which can be described by the diffraction intensity distribution in both 2θ and g directions. The texture information appears in a 2D diffraction pattern as intensity variation in g direction. The intensity variation represents the orientation distribution of the crystallites in a polycrystalline material. The diffraction vector orientation regarding to the sample orientation can be obtained by vector transformation from the laboratory space to the sample space. The fundamental equations for texture analysis are derived from the unit vector expression in the sample space.
Intelligent Microscopy for EBSD Applications
Authors: Fullwood David T. , Adams Brent L. , Rampton Travis , Khosravani Ali , Miles Michael , Scott Jon , Mishra Raj
Published: December 2011

As EBSD techniques improve, researchers are rapidly gaining access to quantities of high-caliber information previously unavailable. However, these benefits bring their own drawbacks. Engineers must either learn to cope with large amounts of data, or they must be more selective about which data is captured. In either case, machine learning techniques may play an important role. Data mining techniques can be used to extract knowledge from large databases, while other machine learning methods enable the identification of critical features, and the efficient search for such features at the data acquisition phase. One particular application of these techniques involves the investigation of fracture and fatigue mechanisms. Methods are required for finding and recording critical event inception. The development of in-situ test equipment, and high-resolution microscopy techniques (such as high-resolution EBSD: HREBSD) have placed invaluable tools into the hands of researchers. Nevertheless, practical considerations limit the volume of material that can be carefully monitored during a given testing regime. Machine learning techniques offer a promising framework for enhancing efficiency in the search for critical events. This paper presents initial efforts to develop an intelligent microscopy environment for EBSD users based upon machine learning methods. The test bed for the study will include ductility studies in magnesium, exploiting recent advances by the authors in the area of HREBSD.
Study of the True Nature of Microband Boundaries in Aluminum with 3D EBSD
Authors: Bassman Lori , George Cassandra , Quadir M. Zakaria , Afrin Nasima , Liu Ben Yue , Soe Brian , Ferry Michael
Published: December 2011

There are two opposing theories regarding the nature of aligned dislocation boundaries generated during plastic deformation of FCC metals: (i) they are oriented along crystallographic planes, and (ii) their alignment is dictated by the macroscopic stress state during plastic deformation. 3D crystallographic orientation data were collected on a volume containing microbands in commercial purity aluminum, and 3D boundaries were reconstructed. Both types of alignment were found in local surface features.
Improving the Reliability of EBSD-Based Texture Analysis by a New Large Area Mapping Technique
Authors: Davut Kemal , Zaefferer Stefan
Published: December 2011

The relevance of EBSD-based investigations for statements on the macroscopic or mesoscopic behavior of materials is critically relying on the statistical representativeness of the data. Particularly, the statistical reliability of the EBSD-based results (e.g. texture, phase fraction or grain size) remains an open question since the areas observed by the EBSD technique are quite small compared to XRD techniques. It has already been shown that covering larger areas and probing more grains with the help of large step sizes is beneficial in terms of representativeness [1]. On the other hand, small step sizes are beneficial in terms of grain reconstruction and data clean-up. However, step sizes significantly smaller than the average grain size of the material lead to either covered areas or number of probed grains being too small to be representative or to very large datasets and correspondingly long measurement times. In this contribution, the benefits of a new mapping technique [1] that joins the advantages of large and small step size measurements will be demonstrated. The representativeness of the EBSD datasets obtained by classical and this new mapping techniques were compared by calculating the pole figure symmetries of a TRIP steel. The results show that the proposed mapping technique significantly improves the reliability and representativeness of EBSD-based texture measurements.
Characterization of Coatings by SEM Based Microdiffraction
Authors: Gundakaram Ravi C. , Pemmasani Sai Pramod
Published: December 2011

The behaviour of a coating is directly related to its microstructure as well as the crystal structure and composition of different phases that are formed in the deposition process. A comprehensive study of the microstructure and local phase assembly in coatings would help in arriving at structure-property correlations that can help understand the coating behaviour. SEM-based diffraction techniques provide a simple method for obtaining local crystallographic information without the need for complex synchrotron sources. In this study, we present a method for characterization of coatings using SEM-based microdiffraction which involves the combined use of the EDS and EBSD capabilities, citing a Ti-Al-Cr-N multilayer coating as an example. The different layers in the coating were observed and the electron beam focused in each region to first obtain Energy Dispersive Spectra and electron backscatter patterns (EBSPs). The elemental constituents were identified from EDS maps and used to shortlist the possible phases present. The diffraction pattern for each possible phase was then calculated and the EBSPs of the observed and calculated patterns were compared for the closest match. The identified phase was then used as an input to set up EBSD scans across the coating. A qualitative picture of the compositional variation in multilayer coatings was obtained that could help in arriving at the exact stoichiometry of the different layers. Hence, SEM-based microdiffraction allows identification of local crystallographic phases and composition, permitting detailed microstructural studies that would find special application in the study of coatings.
Metallographic Preparation for Electron Backscattered Diffraction
Authors: Voos Patrick
Published: December 2011

Electron Backscatter Diffraction measurement can provide much analytical information, such as the phase orientation or material identification. The “Quality” rating of the backscatter diffraction depends on the success rate of indexing. To achieve this, a deformation-free preparation is essential. In recent years most preparation methods have been optimized to contain on average only three to four sample preparation steps. The sample quality is excellent when reflected light microscopy is used. Due to the low information depth of the EBSD measurement (20-100nm), the standard method must be modified. The preparation method must remove the scratches and the underlying damage in order to obtain a high quality EBSD pattern. The optimization can be done by chemo-mechanical polishing, electrolytic polishing or vibratory polishing. Examples are used to show where the limits of the technologies are and to give helpful ‘Hints’ for EBSD sample preparation.
Progress of Recrystallisation in Cold Rolled Austenitic Stainless Steel during Cyclic Thermal Process
Authors: Ravi Kumar B.
Published: December 2011

The present study aims to understand the evolution of microstructure leading to nano/ultrafine grain formation during cyclic thermal process. A commercial grade of AISI 304L austenitic SS was cold rolled which resulted in a creation of a dual microstructure having strain induced martensite (43%) and heavily deformed retained austenite. The dual phase microstructure was subjected to cyclic thermal annealing process at 825 °C. The events occurring in; a) retained austenite and b) reverted austenite formed by phase reversion of strain induced martensite, during annealing treatment, were studied by the Electron backscattered diffraction (EBSD). The study revealed recrystallisation process of the two austenite grains, which resulted into ultrafine grain formation during cyclic thermal process.
Study on Recrystallization Behavior of Nb-1Zr-0.1C Alloy
Authors: Vishwanadh B. , Mirji K.V. , Vaibha K. , Jha S.K. , Ajay Kumar R. , Samajdar Indradev , Srivastava Dinesh , Dey Gautam Kumar , Tewari Raghvendra
Published: December 2011

The Nb-1%Zr-0.1%C (wt%) alloy is one of the most promising refractory metal alloys having an excellent combination of high temperature properties. Such a combination of properties makes it suitable for several structural applications in the Compact High Temperature Reactor (CHTR). In order to produce the alloy in different shape and sizes a new thermo-mechanical route has been established. The central idea behind the development of such thermo-mechanical route is to reduce the working temperature and provide suitable intermediate annealing treatments to develop desired microstructures. The present paper reports about the application of orientation imaging microscopy in optimizing annealing parameters like temperature and time as a function of the extent of deformation. Samples were also characterized by optical microscopy and transmission electron microscopy techniques. It has been shown that a heat treatment of 1300°C for 3 hour could produce nearly full-recrystallized microstructure. This paper also discusses about the carbide precipitation, their morphologies, chemical compositions and orientations with the matrix phase.
Vertex Dynamics Simulations of Orientation Dependent Recovery in Deformed Aluminium Single Crystals
Authors: Majumdar Adhish , Maurice Claire , Driver Julian H.
Published: December 2011

A 2-dimensional vertex dynamics simulation is applied to the annealing behaviour of deformed Aluminium single crystals having different orientations. It is observed in experiments that deformed single crystals of different orientations - typically the common rolling textures like Goss (110)[001], Brass (110)[1-12], Cube (001)[100] – exhibit remarkably different rates of recovery. It is suggested that this difference arises from the deformation microstructures, with sub-grain boundaries of various misorientation values. The sub-grain boundary mobilities and energies, being strong functions of the boundary misorientation, thus affect the recovery rates. This effect is illustrated using vertex dynamics simulation on the same orientations and schematic deformation substructures as above. Good agreement is obtained for the orientation dependency of recovery.
Directional Anisotropy in the Mechanical Behavior of Friction Stir Processed and Aged AZ91 Alloy
Authors: Jain Vipin , Yuan Wei , Mishra R.S. , Gouthama  , Gupta Anil K.
Published: December 2011

Friction stir processing (FSP) is an emerging grain refinement technique for magnesium alloys. In this study, a cast AZ91 alloy was processed by a single-pass FSP to achieve an average grain size of ~6 mm in the nugget zone. The FSP is found to introduce texture in the alloy due to preferred alignment of basal poles in the processing direction. The mechanical behavior is significantly influenced by texture. After FSP, the alloy was aged at different temperatures and times for continuous and discontinuous precipitation of b-Mg17Al12. A high anisotropy in yield stress is observed in the processing and transverse direction after FSP. It is shown that this anisotropy can be minimized under optimum ageing conditions. The observed yield asymmetry is correlated with the texture variation after FSP. The role of b-Mg17Al12 precipitates in reducing the yield anisotropy is also discussed.
An EBSD Study of Texture Variation along Pilger Reduced Titanium Alloy Tubes
Authors: Ubhi Harvinder Singh , Houghton Andrew , Saithala Janardhan
Published: December 2011

This study investigates the changes in radial micro-texture via Kearn’s f-factors during single cold pilger reduction of a titanium Ti-3-2.5 alloy as a result of strain path changes from tooling modifications. EBSD results confirm that the texture intensity as well as the radial f-factors can be increased by modifications of pilgering tooling. In addition a switch between the secondary prism planes which lie normal to the pilger direction in the starting tube to primary prism planes after pilgering has been observed.
Influence of Rare Earth Addition on Texture Development during Static Recrystallization and Mechanical Behaviour of Magnesium Alloy Sheets
Authors: Yi Sang Bong , Rayas Lilian , Sandlöbes Stefanie , Zaefferer Stefan , Letzig Dietmar , Kainer Karl Ulrich
Published: December 2011

The role of rare earth addition on the microstructure and texture during recrystallization of cold rolled sheets is investigated by a comparative study of pure Mg, Mg-3Y and Mg1.5Nd sheets. In pure Mg, nucleation occurs mainly at shear bands which results in a texture weakening. The basal-type texture re-strengthens rapidly during grain growth of the pure Mg sheet. In contrast, in the Mg-RE alloys the weaker texture formed during early recrystallization strage is retained during further annealing due to retarded grain growth. Uni-axial tensile and Erichsen tests show that ductility and sheet formability are significantly improved by addition of rare earth elements.
Study of the Microstructure, Texture and Tensile Properties in as-Extruded AZ91 and ZM21 Magnesium Alloys
Authors: Thirumurugan M. , Madhavan R. , Kumaran S. , Rao T. Srinivasa , Suwas Satyam
Published: December 2011

In this paper, the microstructure, texture and tensile properties of the magnesium alloys AZ91 and ZM21 extruded at 350°C to the ratio 25:1 are investigated. After extrusion, the mean grain size reduces from 400 µm to 30 µm in ZM21 alloy and from 350 µm to 40 µm in AZ91 alloy. Bulk texture analysis indicates the formation of characteristic extrusion texture in both the alloys. The occurrence of dynamic recrystallization, as revealed through necklace structure formation, and the precipitation of second phase (Mg17Al12) particles in the AZ91 alloy are observed.
Modelling Static Recrystallisation Textures Using a Coupled Crystal Plasticity-Phase Field Technique
Authors: Lan Yong Jun , Pinna C.
Published: December 2011

An integrated crystal plasticity-phase field model has been developed to simulate the static recrystallisation textures of both Face-Centred Cubic (FCC) and Body-Centred Cubic (BCC) metals. Nucleation sites are determined using the Orientation Dependent Recovery (ODR) theory. Both the interface mobility and the grain boundary energy are set to be dependent on mis-orientation angles in the simulations. A pre-deformed microstructure without a particular texture is generated using a Monte Carlo simulation. Plane strain compression textures before recrystallisation are predicted by a Crystal Plasticity Finite Element (CPFE) model showing a good agreement with the typical experimental rolling textures. It is shown that the typical recrystallisation textures for FCC and BCC metals can be simulated correctly using a Phase Field (PF) method by choosing appropriate critical values for the nucleation criterion. A comparison between the two different nucleation criteria based on the ODR theory or the stored energy is also presented.
Study on Sensitization Susceptibility and Texture of Cold Rolled AISI 304LN Stainless Steel
Authors: Singh Raghuvir , Ghosh Chowdhury Sandip , Das Gautam , Singh P.K. , Chattoraj Indranil
Published: December 2011

Attempt has been made to correlate the cold rolling (CR) texture with the degree of sensitization (DOS) in rolled 304LN after ageing at 500-600oC for various durations. The susceptibility of sensitization is observed to increase with %CR cold rolling from 5-25% and aged at 500-600oC. No one to one correlation between texture and DOS is observed. Brass component, overall, seems better for lower DOS while Goss component led to relatively higher DOS values. It is observed that the ratio of Brass to Copper may have a critical value for lower DOS.
Non-Uniform Strain Hardening of Crystallites within Different Regions of Texture Maxima: Evidences and Mechanisms
Authors: Perlovich Yuriy , Isaenkova Margarita
Published: December 2011

Abstract. Experimental evidences of regular differences in the substructure condition of grains depending on their position within texture maxima are demonstrated. Analysis of generalized pole figures (GPF) for rolled metal materials shows that the strain hardening intensifies as an angular distance of grains from the texture maximum centre increases. The mechanisms of this phenomenon are considered using the concepts of the texture formation theory.
IGSCC of Non-Sensitised Austenitic Stainless Steels in BWR Environment – Effect of Deformation Mode on Grain Boundary Susceptibility
Authors: Roychowdhury Supratik , Kain Vivekanand , Gupta M. , Neogy S. , Srivastava Dinesh , Dey G.K. , Prasad R.C.
Published: December 2011

Intergranular Stress Corrosion Cracking (IGSCC) of austenitic Stainless Steels (SS) in Boiling Water Reactor (BWR) environment is generic in nature in both the sensitised and the non-sensitized conditions. IGSCC in non-sensitized austenitic SS in the strain hardened condition has been reported without any grain boundary chromium depletion or impurity segregation. The present study ascertains the reason for IGSCC in BWR environment in non-sensitized condition and investigates the effect of nitrogen content in SS on the susceptibility to IGSCC. Two heats of type 304LN stainless steel with 0.08 and 0.16 wt. % nitrogen were used. Strain hardening was done by cross rolling at 200 °C to 20 % thickness reduction (warm rolling) to simulate the weld induced strain in constrained welds. Subsequently, Transmission Electron Microscopic (TEM) examination was carried out on the rolled SS. The deformation mode observed due to warm rolling was predominantly elongated twin and shear band (SB) formation in both the SS, terminating at the grain boundary regions. This resulted in higher stresses and strains making grain boundary susceptible to IGSCC. Presence of more dislocations at grain boundaries is a key feature for such enhancement in the susceptibility of non-sensitized SS to IGSCC. Formation of twins and SB occurred to a greater extent in the SS with higher nitrogen content indicating greater susceptibility to IGSCC in BWR environment. Crack growth studies done in simulated BWR environment at different Dissolved Oxygen (DO) levels showed higher crack growth rates in the SS with higher nitrogen content in the non-sensitised and strain hardened condition, confirming the higher susceptibility of SS with a higher level of nitrogen.
End Grain Corrosion: Establishing Microstructural Causes and Preventive Steps
Authors: Khan Shagufta , Chandra Kamlesh , Kain Vivekanand , Reddy A.V.R.
Published: December 2011

Nuclear spent fuel reprocessing and waste management plants use nitric acid as process fluid and type 304 L stainless steel as construction material. Tubular products like bars, tubes and pipes are prone to End Grain Corrosion from the exposed cross-sectional surfaces. In this study, type 304 L stainless steel is subjected to different heat treatment to induce selective segregation of phosphorus. The susceptibility to End Grain Corrosion was established in tests using boiling nitric acid containing oxidizing Cr(VI) ions. A clear effect on End Grain Corrosion was found for heat treatment reported to induce phosphorus segregation. Finally, specific annealing heat treatment is developed that erases out the segregation, without affecting the grain size or sensitization.
Importance of Microscale Texture and Grain Boundary Connectivity to Percolation-Dependent Bulk Properties in Polycrystalline Materials
Authors: Watanabe Tadao , Kobayashi Shigeaki , Zhao Xiang , Zuo Liang
Published: December 2011

Bulk properties of polycrystalline structural and functional materials are controlled by the grain boundary microstructure defined by the grain boundary character distribution (GBCD) and grain boundary connectivity, because of percolation-dependent grain boundary phenomena. It has been found that there is a close relationship between microscale texture and grain boundary microstructure. Since percolation-controlled grain boundary phenomena are involved and playing key roles in the generation of various kinds of bulk properties, the relationship between texture and grain boundary microstructure can be effectively used as a powerful tool in development of high performance structural and functional materials by Grain Boundary Engineering (GBE).
Modeling the Magnetic Properties of Non-Oriented Electrical Steels Based on Microstructural Parameters
Authors: Pirgazi Hadi , Petrov Roumen H. , Kestens Leo A.I.
Published: December 2011

Magnetic properties of electrical steels such as magnetization behavior and electrical losses are mainly related to chemical composition, crystallographic orientation and microstructure. By now, several models have been proposed to empirically correlate magnetic properties and affecting parameters. A quantitative model based on physical understanding of the interaction between the magnetic field variables (e.g. domain structure) and local microstructural variables (e.g. grain orientation and misorientation, grain boundary plane inclination) is still missing. To obtain a better understanding of the interaction between grain boundaries and domain walls, the magnitude of free pole density at grain boundaries was taken into account. Experimental results from 3-dimentional EBSD experiments were employed to measure the grain boundary orientation for several samples with different chemical composition and grain size. The free pole density was calculated using the relative misorientation between adjacent grains, and was included in a model together with grain size, magnetocrystalline anisotropy energy and silicon equivalent. By comparison with the experimental results of the magnetic induction measured at low, medium and high magnetic fields, is shown that the magnetization behavior can be more accurately predicted when the above mentioned phenomena are taken into account.
Effect of Rolling Temperature on the Evolution of Microstructure, Texture, and Mechanical Properties of AZ31 Mg Alloy
Authors: Park No Jin , Hwang Sun Hea
Published: December 2011

Magnesium alloys have attracted a great deal of attention and have been extensively studied, but there is still a major obstacle to their practical application, namely, their poor formability at room temperature, which basically originates from their insufficient number of slip systems. The development of a microstructure and/or texture that is more conducive to formability is one promising solution that could improve their formability. In the present work, the microstructures, textures, and tensile properties of AZ31 Mg alloys are studied following extrusion and full annealing and rolling at 100 and 300°C. After full annealing, a strong ∥ED fiber texture and a weak + ∥ED fiber texture (c-axes in the radial direction) were developed. After 40% rolling at 100°C, many deformed twins were observed and a relatively weak texture was developed. The basal poles were split and rotated about 20° to the rolling direction (RD). During 60% rolling at 300°C, dynamic recrystallization (DRX) took place and a strong ∥ND fiber texture was developed, and this had an influence on the alloys’ poor formability at room temperature.
Through-Thickness Shear Strain in Silicon Steel under Asymmetric Rolling
Authors: Yang H.P. , Sha Yu Hui , Zhang Fang , Pei Wei , Zuo Liang
Published: December 2011

Through-thickness shear strain variation with speed/radius/friction ratio in cold rolled silicon steel under different asymmetric rolling modes was analyzed by finite element method (FEM). Cold rolling textures were also investigated quantitatively to correlate with the calculated shear strain. With increasing speed/radius/friction ratio, shear strain distribution under differential-speed and differential-radius rolling exhibits similar characteristic in contrast to differential-friction rolling. Unidirectional shear strain develops through sheet thickness when asymmetric speed and radius ratio exceeds 1.125, whereas it does not appear even at friction ratio of 1.5. Shear strain distribution dependent on asymmetric rolling modes can be well understood by forward and backward slip zones as well as roll pressure as a function of speed/radius/friction ratio.
Effect of Grain Size and Meso-Texture on the Impact Toughness of Ti-Microalloyed Steel
Authors: Ray A. , Chakrabarti Debalay
Published: December 2011

Charpy impact testing (over the transition temperature rage) on different samples of a Ti-microalloyed steel, having the same average-TiN particle size but different average-ferrite grain sizes, showed that in spite of the presence of large TiN cuboides, ferrite grain refinement can significantly improve the impact toughness, provided the meso-texture (i.e. the intensity of low-angle boundaries) and matrix strength can be restricted to low values.
Texture Formation in High Strength Low Alloy Steel Reheated with Ultrafast Heating Rates
Authors: Petrov Roumen H. , Sidor Jurij J. , Kestens Leo A.I.
Published: December 2011

Texture formation during annealing of a 95% cold rolled HSLA steel with 10°C/s and ~3000°C/s was studied with the purpose to investigate the interaction between the recrystallization and the austenite formation as well as the possibility of grain refinement. The recrystallization and austenite formation were monitored by means of optical microscopy (OM), scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). It was found that at extreme reheating rates of 1000°C/s and higher, the α-γ phase transformation starts before the completion of recrystallization and the deformation texture is partially retained in the samples after annealing. The crystallographic texture observed in the martensitic phase which is the product of intercritical austenite transformation in as-quenched samples, i.e. after the double α-γ-α’ transformation, is the same as the initial cold rolling texture, which is an indication for the texture memory effect. After ultra fast reheating with average reheating rates of 1000°C/s and higher a significant grain refinement was observed with an average ferrite grain size of ~1µm. The obtained final ferrite grain size depends significantly on both the reheating temperature and the reheating rate.
Study of Texture in Ultra Fine Grained Dual Phase Steel Sheets
Authors: Mondi Papa Rao , Madhavan R. , Sarma V. Subramanya , Sankaran S.
Published: December 2011

Severe cold rolling and short intercritcal annealing is often used to produce ultra-fine grained ferrite and martensite dual phase steels. In this paper, microstructure and texture of Nb-microalloyed steel following cold rolling and short intercritical annealing is investigated. The results show that cold rolling and annealing resulted in ultra-fine grained dual phase steel consisted of polygonal ferrite in the range of ~1-2 μm in size. In cold rolled material, the texture components are γ fiber (//normal direction) and α fiber (//rolling direction). Partial recrystallization texture was observed following intercritical annealing.
Deformation Behaviour of Titanium in Torsion
Authors: Gurao Nilesh P. , Suwas Satyam
Published: December 2011

The evolution of microstructure and texture in Hexagonal Close Pack commercially pure titanium has been studied in torsion in a strain rate regime of 0.001 to 1 s-1. Free end torsion tests carried out on titanium rods indicated higher stress levels at higher strain rate but negligible change in the strain-hardening behaviour. There was a decrease in the intra-granular misorientation while a negligible change in the amount of contraction and extension twins was observed with increase in strain rate. The deformed samples showed a C1 fibre (c-axis is first rotated 90° in shear direction and then +30° in shear plane direction) at all the strain rates. With the increase in strain rate, there was an increase in the intensity of the C1 fibre and it became more heterogeneous with a strong {11 6} component. In the absence of extensive twinning, pyramidal slip system is attributed for the observed deformation texture. The present investigation, therefore, substantiates the theoretical prediction of increase in strength of texture with strain rate in torsion.
Texture and Microstructure Development during Swaging and Annealing Process of Fabrication of Zircaloy-4 Rod Products
Authors: Neogy S. , Acharya S. , Mani Krishna Karri V. , Srivastava Dinesh , Dey G.K. , Phani Babu C. , Das Gourahari , Raut B. , Chaube R.K. , Jha S.K. , Prahlad B. , Saibaba N. , Kumar A. , Samajdar Indradev
Published: December 2011

In this study a systematic characterization of the microstructural and textural evolution in each thermo-mechanical processing step of Zircaloy-4 rod fabrication has been carried out. The possible micro-mechanisms leading to the observed microstructural evolutions have been discussed. The thermo-mechanical steps followed resulted in a completely recrystallized microstructure and retention of the hot-extruded texture in the finished product.
Determination of Crystallographic Elements (Dislocation and Surface Plane) from Automated TEM Orientation Determination
Authors: Zhang Yu Dong , Wang Shi Ying , Esling Claude , Zhao Xiang , Zuo Liang
Published: December 2011

Abstract In the present work, we summarized two calculation methods to determine some specific crystallographic elements based on electron diffraction orientation measurements performed by TEM. The first one is to determine the type and the Burgers vector of dislocations for a known crystal structure. The method calculates the orientation of the projections of all the possible dislocation line vectors in the TEM screen coordinate system using the determined crystallographic orientation of the grain and then compares them with the observed ones to identify the observed dislocations. The second is to characterize the surface crystalline planes and directions of faceted nano-particles. With the determination of the edge trace vectors and then the plane normal vectors in the screen coordinate system of the TEM, their Miller indices in the crystal coordinate system can be calculated through coordinate transformation. These methods are expected to facilitate the related studies.
Microstructural Irreversibilities under Thermal Cycling in Ni-Ti-Fe Shape Memory Alloys
Authors: Basu Ritwik , Jain Lokendra , Maji Bikas , Krishnan Madangopal , Mani Krishna Karri V. , Samajdar Indradev , Pant Prita
Published: December 2011

The thermal cycling (quenching in liquid nitrogen and reverting back to room temperature: austenite martensite reversible transformation) response of Ni-Ti-Fe shape memory alloys has been investigated. It was clearly noted that residual deformation, estimated in terms of noticeable differences in austenite grain size, depend on the relative clustering of fine grains. During repeated thermal cycling, the residual deformation, in-grain misorientation developments and retained martensite content scaled together: bringing out a clear picture of microstructural irreversibility.
Texture of Electrodeposited Nanocrystalline Ni-Fe with Banded Structure
Authors: Klement Uta , Shahabi-Navid Mehrdad , Hibbard Glenn D.
Published: December 2011

Optical microscopy on the etched cross-section of a nanocrystalline Ni-18 wt.% Fe electrodeposit revealed the existence of a banded structure perpendicular to the growth direction. To evaluate if the banded structure is affecting grain growth and texture development, EBSD orientation maps were obtained after annealing for 30 min at 300, 350, and 400°C. Grown grains were found to be random in shape and no preferential sites for grain growth were observed. The texture of the grown grains is changing upon annealing and the final fibre texture parallel to growth direction of the electrodeposit can be obtained from texture components found at lower annealing temperatures when performing one or two consecutive twinning operations.
Effect of Environment on the Surface Modification by Pulse Laser Irradiation of Al-Si/SiCP MMCs
Authors: Mahanty Soumitro , Gouthama  , Mandal Tapendu
Published: December 2011

MMCs (Metal Matrix Composite) are very useful in the different branch of application like aerospace, automobile engineering and defense application. Of late surface modification of variety of materials is gaining importance. Various surface modification techniques are being used some at research scale and some at industrial scale. In the present study, an attempt has been made to modify the surface of Al-Si/SiCP metal matrix composite using KrF Excimer laser and to study the microstructural changes using optical microscopy and SEM imaging and EDS analysis. Results from the study are presented and discussed.
Favorable Effect of Ho Addition on the Microstructure and Magnetostriction of Textured Tb0.3Dy0.7Fe1.95
Authors: Chelvane J. Arout , Palit M. , Basumatary H. , Banumathy S. , Singh A.K. , Pandian S.
Published: December 2011

This paper reports the effect of Ho on the microstructure, texture and magnetostrictive properties of Tb0.3Dy0.7-xHoxFe1.95 (with x = 0, 0.05, 0.1, 0.15 and 0.2) alloys. The alloys were vacuum induction melted and directionally solidified by modified Bridgman technique. Ho addition has been found to improve the magnetostriction at lower concentration due to absence of deleterious pro-peritectic (Tb,Dy)Fe3 phase. The static strain co-efficient is found to be better in Ho added alloys and the prevalence of strong and texture is attributed to be the reason.
Structure-Property Correlations in Cathodic Arc Deposited TiAlN Coatings
Authors: Pemmasani Sai Pramod , Valleti Krishna , Ramakrishna M. , Rajulapati K.V. , Gundakaram Ravi C. , Joshi S.V.
Published: December 2011

PVD hard coatings, notably transition metal nitrides and carbides, are being increasingly used by industry for improving the life and machining speeds of cutting and forming tools. There has been an increasing trend towards use of complex coatings, based on ternary and even more complex multi-component systems, as well as in novel configurations such as multilayers, superlattices, nanolayers and graded coatings, to achieve superior properties in the tool as well as the finished product. The service properties of the coatings are known to be influenced by their microstructure, phase assembly and composition, apart from the orientation and stress states which can be suitably tailored for diverse applications. In the present study, a ternary coating based on Titanium Aluminum Nitride was deposited on high speed steel substrates by cathodic arc evaporation under varied bias voltage conditions. As-deposited coatings were characterized by X-ray diffraction, Residual Stress Analysis, Scanning Electron Microscopy (SEM), EBSD and FIB. Mechanical and tribological characteristics of the coatings were evaluated by nanoindentation and nanoscratch testing, respectively. The variations in coating hardness and adhesion with the bias voltage were studied. The changes in coating microstructure as a consequence of variation in bias voltage were also examined. Results from the above investigations are presented to illustrate how a combination of electron microscopy with nanoindentation and adhesion testing can be utilized to ascertain structure-property correlations in coatings.
The Redistribution and Alignment of Crystalline Flakes in a Bulk Metallic Glass Composite during Thermoplastic Forming
Authors: Xu Wan Qiang , Robin Lalu , Laws Kevin J. , Zheng Rong Kun , Ferry Michael
Published: December 2011

An In-situ Mg-based bulk metallic glass (BMG) composite containing 40% volume fraction of Mg-rich crystalline flakes was produced by die casting. During cooling from the melt, the flakes nucleate heterogeneously and subsequently grow with their broad faces parallel to the {0001} plane. This generated a uniform dispersion of randomly-oriented flakes within an amorphous matrix. When compressed uniaxially up to 60% reduction in the supercooled liquid (SCL) region, the flakes in this composite were substantially aligned their broad faces towards the compression plane that generated a strong //ND fibre texture.
Effect of Modes of Rolling on Evolution of Texture and Yield Locus Anisotropy in a Multifunctional Ti-31Ta-12Nb-2V-8Zr-0.22O Alloy
Authors: Premkumar M. , Himabindu V.S. , Banumathy S. , Bhattacharjee A.K. , Singh A.K.
Published: December 2011

Present work describes the evolution of texture during different modes of deformation by cold rolling of a Gum metal or multifunctional β titanium alloy. The starting and cold rolled materials exhibit the presence of β and β with small amount of stress induced martensitic (α˝) phases, respectively. The development of texture has been explained in terms of α and γ fibres. The bulk hardness appears to be independent of modes of deformation by cold rolling. The yield surfaces of as received and solution treated samples exhibit marked anisotropy which persists during different modes of deformation by rolling.
Multirange Fractal Analysis of Discontinuous Microstructure Change of In-40wt.%Sn Melt
Authors: Zhou Yong Zhi , Geng Hao Ran , Li Mei , Sun Chun Jing , Wang Zhi Ming
Published: December 2011

Fractal analysis based on results of high temperature X-ray diffraction experiment was used to study the temporal-spatial properties of particles in In-40wt.%Sn melt. Partially-overlapping multirange fractal structure is observed in In-40wt.%Sn melt, and as temperature decreases from 800°C to 130°C, low fractal dimension was found to range between 2.000 and 2.669, high fractal dimension is still 3.000 without alteration. Moreover, low fractal dimension reveals a discontinuous change between 600°C and 700°C. Fractal characteristics of In-40wt.%Sn melt were correlated with the evolution of microstructure. The discussion was made in detail. Multirange fractal model was proposed to calculate transition region curves of multirange fractals. The results show that values of simulation show good agreement with experimental values, the maximum error is less than 1.3%. From the analysis, the range of the transition region between two fractal regions is speculated to be related with structure properties of metal melts. In addition, ultrafine particles’ aggregation mechanism was used to analyze the fractal morphologies. Keywords: multirange fractal; In-40wt.%Sn melt; microstructure change; X-ray diffraction.
Metallic Tribological Compatibility of Moss-Toughened Mo2Ni3Si Metal Silicide Alloys
Authors: Gui Yong Liang , Qi Xue Jing , Song Chun Yan
Published: December 2011

A noval wear resistant Moss-toughened Mo2Ni3Si metal silicide alloys was designed and manufactured with the commercial Mo, Ni and Si powders. Wear resistance of the alloys was evaluated under dry-sliding wear test condition at room temperature. Results show that the alloys have excellent wear resistance and tribological compatibility coupling with conventional metallic materials due to the high hardness and strong atomic bonds of the ternary metal silicide Mo2Ni3Si with MgZn2 type Laves crystal structure.
Microstructure of Aluminum Bronze Coating Sprayed by Cold Gas Dynamic Spraying (CGDS)
Authors: Liu Yu Liang , Xiong Tian Ying , Wu Jie
Published: December 2011

Cold Gas Dynamic Spraying (CGDS) has been developed to fabricate surface coating as a new technique in recent years. In this paper, aluminum bronze particles were sprayed on 45 steel and 316L stainless steel by CGDS, and the coating was sucessfully fabricated on the surface of the steels. The microstructure of the coating and the interface between the coating and the substrate were investigated by scanning electron microscope (SEM), energy dispersive (EDX) and XRD. It was found that the coating was dense and its porosity was low, while the microhardness of the coating was lower than that of the bulk one; Mechanical bonding was the main formation mechanism of the coating, and there was metallurgical bonding too; Diffusion occured at the interface between the coating and substrate; α phase in aluminum bronze particles transformed to β phase after the spray and the transformation was induced by the plastic strain during spraying.
Analysis of Unit and Binary Diffusion in Glow Plasma Surface Alloying Process
Authors: Chen Xuan Nan , Gao Yuan , Li Bing , Huang Xue Feng
Published: December 2011

Q195 steel was conducted by plasma chromizing and Cr-Ni surface alloying process to research the relationship between unit diffusion and binary diffusion. After studying the thickness, composition, phase component of the layer and diffusion coefficients of alloying elements, results showed that (1) the thickness of chromizing layer was 150μm; the surface phase component was Fe-Cr solid solution; the surface chromium contents was 21.4%. The thickness of Cr-Ni co-diffusion layer was 40μm; the surface phase component was Fe-Cr-Ni solid solution; the surface contents were: Cr 16.14%, Ni 48.16%. The alloying elements distributed in downward gradient from the outside to the inside. (2) Compared with plain surface alloying technique, using plasma surface alloying technique can get higher diffusing speed and shorten production cycle time. (3) The diffusion coefficients decreased as the diffusion distance increased. (4)Compared with chromizing, Cr-Ni co-diffusion increased the utilization ratio of alloying elements but decreased the diffusion speed of alloying elements, thus the surface alloying content increased and the thickness of alloying layer decreased.