Recrystallization Orientations Research Articles

Low‐Temperature Annealing of Asymmetrically Cold‐Rolled Electrolytic Tough‐Pitch Copper: Anneal Hardening and Bimodal Microstructure

In this research, 90% asymmetric unidirectional rolling and post‐annealing are applied to electrolytic tough‐pitch (ETP) copper. The effect of low‐temperature (200 °C) annealing on the microstructure and texture evolution, mechanical, and electrical properties are investigated. Static recovery (SRV) is the main softening mechanism at the annealing time range of 1–5 min. In contrast, complete static recrystallization (SRX) is observed after annealing for 10 min. Bimodal microstructure, consisting of coarse and fine grains, is evolved for annealing times more than 10 min. With increasing the post‐annealing duration, the intensity of deformation and shear textures is continuously decreased; however, the recrystallization (Cube) orientation becomes stronger up to 11.2 × R. After 1, 2, and 5 min of post‐annealing, the hardness, yield strength, tensile strength, ductility, and toughness of copper are higher than those of the 90% rolled sample due to annealing hardening. After 10 min of annealing, the hardness, yield strength, and tensile strength suddenly decrease and the ductility and toughness significantly enhance owing to the complete recrystallization. With increasing the post‐annealing time, the fraction of flat surfaces is decreased and the fraction of ductile dimples is increased. With the post‐annealing time increasing from 1 to 120 min, the electrical conductivity gradually increases from 84.9%IACS to 96.7%IACS.

Special texture evolution behavior of strip-cast non-oriented electrical steel combined with in-situ experiment and CPFEM

The impact of shear deformation on texture evolution in strip-cast Fe-1.5%Si non-oriented electrical steel was studied combined with in-suit experiments and crystal plasticity finite element method (CPFEM). Throughout the deformation process, the texture evolution predominantly follows a traditional route: transitioning from {211}<036> and {411}<148> to {111}<112> orientation. In certain regions with specific stress conditions, orientation evolution shifts from {310}<236> to {411}<148>, {100}<021>, and finally to {100}<001> orientation. Crystal plasticity finite element (CPFE) simulation results show that the rotation of {310}<236> through {411}<148> to {100}<021> orientation, {211}<236> and {112}<110> orientations transition to {111} and {110} orientations, respectively, which is consistent with the experimental observations. Recrystallization texture mainly includes favorable λ and near-λ (<100>∥ND, normal direction) textures, with detrimental γ (<111>∥ND) texture essentially diminishing. In-situ heating experiments revealed {411}<148> as the primary recrystallization orientation, the mechanism involves both oriented nucleation and growth. In the edge region lacking stress constraints, the Schmid factor (SF) reaches up to 0.48, the (21-3)[111] slip system is preferentially activated, with shear bands appearing earlier in the same region. Indicating that when slip mechanism alone are inadequate for sustaining plastic deformation, the shear deformation becomes the favored mode of activation. {411}<148> orientation can serve as a transitional orientation for transitioning to {100} orientation, and further as an advantageous transitional orientation during the nucleation and growth of recrystallization. Due to the texture improvement, superior magnetic properties were achieved, with the average magnetic induction (B50) and iron loss (P1.5/50) being 1.77 T and 4.25 W/kg, respectively.

Evolution of recrystallization texture in nickel-iron alloys: experiments and simulations

ABSTRACT The present work is aimed at examining the effect of solid solution on the development of recrystallization microstructure and texture in FCC materials where SFE remains unchanged on alloying addition. To elucidate the mechanisms of texture formation during recrystallization, pure Ni and Ni-Fe (20 and 40 wt.% Fe) alloys were investigated. After recrystallization, pure Ni showed a cube and a non-uniform α-fibre texture, whereas the Ni-Fe alloys showed a texture characterised by the rotated cube component, brass recrystallization (BR) orientation, and a non-uniform α-fibre. Addition of Fe to pure Ni has led to some fine differences in the recrystallization texture that have been attributed to the role of highly heterogeneous deformed microstructure in the Ni-Fe system because of alloying. However, in all the cases Cu-oriented grains are prone to early recrystallization due to relatively more heterogeneously deformed regions, whereas deformed grains having orientation <110> || ND have shown slow recrystallization. In all cases, the entire stage of recrystallization is dominated by the formation of annealing twin (Σ3) boundary. The mobility of these twin boundaries plays an important role in the evolution of the recrystallization texture, which in turn, depends on its coherency, i.e. grain boundary plane (K1) of twin boundaries. The mechanism of evolution of recrystallization texture and the role of different deformation features during recrystallization is investigated. The cellular automata simulation technique was used to simulate the recrystallization behaviour of the alloys. The simulation results were used to discuss experimental observations.

Effects of Strain Rate on Shear Bands and Texture Evolution in Grain-oriented Silicon Steel

The effects of strain rate on shear bands and texture evolution of grain-oriented silicon steel were investigated by adjusting the strain rate of warm rolling. The rolling experiment was carried out at different strain rates of 30s-1, 50s-1 and 70s-1. XRD, EBSD and TEM were used to investigating the effect of the strain rate on the formation of shear bands and texture evolution. The results show that when strain rate increases during warm rolling, the texture strength of {111 }<112> deformation matrix increases at 70% and 85% reduction. The number of Goss shear bands increases, which is beneficial to obtain the ideal recrystallization orientation. With the increase of the reduction (70-85%), the recrystallized Goss texture strength decreases. This phenomenon diminishes with increasing strain rate, because the increase of dislocation density slows down the death process of shear bands.

Influences of cold rolling, recrystallization and surface effect on the transformation textures in a TA10 titanium alloy

A transformation treatment based on surface effect induced transformation is applied to cold rolled TA10 titanium alloy sheets to change and control transformation texture. This kind of treatment can promote the α-phase nucleation at sheet surface region during cooling and control the growth of surface α-grains into center layer of sheet. The results indicate that as the heating temperature increased, the transformation textures in the final HCP-structured TA10 sheets changed in helium atmosphere from the recrystallization type texture of <11-20>//RD to the transformation type texture of <11-20>//ND. The textures in sheets treated at low transformation temperature of 1000°C reveal texture memory effect, while those treated at high transformation temperature of 1100°C illustrate the effects of both transformation strain and anisotropy in elastic modules of HCP titanium crystals. The surface effect is promoted by cooling gas of helium, which leads to layered structures along sheet thickness direction. The surface region often shows small equiaxed grains with recrystallization orientations, while the center layer reveals coarse grains with either plate-like or equiaxed grain morphology corresponding to transformation orientation or recrystallization orientation, respectively. The special grain boundaries in plate-like α variants are different from those in equiaxed grains. These differences in morphologies, sizes and orientations are explained in terms of the mechanism change of the factors affecting variant selection.

Role of crystallographic misorientations in the evolution of texture in FCC metals

The features of recrystallization texture by orientation microscopy (EBSD) in rolled aluminum wire are investigated. Strict crystallogeometric correlations between deformation orientations and recrystallization orientations are the result of the dominant role in structural transformations of special misorientations – the special boundaries that are close to Σ25b or Σ45c in the CSL model.

Primary Recrystallization Texture in FCC-Metal with Low Packing Defect Energy

The method of orientation microscopy (EBSD) is used to study the special features of recrystallization texture in drawn copper wire. It is shown that the strict crystallographic relationships between deformation and recrystallization orientations are consequences of the dominant role in structural transformations of special misorientations, i.e. special boundaries. Mechanisms of the appearance and “growth” of annealing twins are proposed.

Modelling the evolution of recrystallization texture for a non-grain oriented electrical steel

A new methodology based on the strain energy release maximization (SERM) theory and Avrami-type kinetics is introduced to predict the evolution of recrystallization texture in a non-grain oriented (NGO) electrical steel. The deformation orientation and the activated slip system of each orientation, which can be developed by cold rolling for a hot-rolled NGO electrical steel, were calculated using the finite element method and visco-plastic self-consistent model. Afterwards, the recrystallization orientations that can evolve from each deformation orientation were determined by the SERM theory, and their fraction over the annealing time was calculated based on the Avrami-type kinetic equation. As a result, this approach for the NGO electrical steel could successfully predict the formation of γ-fiber with strong {1 1 1}〈1 1 2〉 component during recrystallization, which was in good agreement with the experimental results.

Effects of asymmetric rolling process on ridging resistance of ultra-purified 17%Cr ferritic stainless steel

In ferritic stainless steels, a significant non-uniform recrystallization orientation and a substantial texture gradient usually occur, which can degrade the ridging resistance of the final sheets. To improve the homogeneity of the recrystallization orientation and reduce the texture gradient in ultra-purified 17%Cr ferritic stainless steel, in this work, we performed conventional and asymmetric rolling processes and conducted macro and micro-texture analyses to investigate texture evolution under different cold-rolling conditions. In the conventional rolling specimens, we observed that the deformation was not uniform in the thickness direction, whereas there was homogeneous shear deformation in the asymmetric rolling specimens as well as the formation of uniform recrystallized grains and random orientation grains in the final annealing sheets. As such, the ridging resistance of the final sheets was significantly improved by employing the asymmetric rolling process. This result indicates with certainty that the texture gradient and orientation inhomogeneity can be attributed to non-uniform deformation, whereas the uniform orientation gradient in the thickness direction is explained by the increased number of shear bands obtained in the asymmetric rolling process.

Relationship between Deformation and Recrystallization Texture in Copper Wire

Using electron backscatter diffraction (EBSD), the relationship between deformation textures, developed upon different stress-strain states and characterized by the basic crystallographic orientations of recrystallized grains, has been studied in a FCC metal. The regularities of recrystallization twins development were considered. Crystallo-geometric relations between the deformation and the recrystallization orientations were explained with the mobility of the special grain boundary close to the coinciding site lattice boundary Σ25b. Mechanisms of nucleation and growth of the annealing twins were proposed.

Texture of Hot-Rolled Sheet Fe-3% Si Alloy

Using the method of orientation microscopy, based on electron backscatter diffraction (EBSD), the texture of Fe–3% Si alloy sheet, produced by hot rolling at 1280 – 920 °C with a total strain exceeding 95 %, was characterized. The texture sheet in the surface region and in the central region consists of a set of stable orientations. The surface region mainly consists of recrystallization orientations; the texture of the central region is formed by a set of deformation orientations. The surface orientations of the sheet are rotated by 90° around the transfer direction relative orientations of the central region. The recrystallization texture components reproduce deformation texture components. Recrystallization replaces texture in the local region. With transverse flow (near the edges) in hot rolling, the stable orientation {112}&lt;110&gt; is formed in the surface region. The recrystallization process does not take place at the edges of the strip.

Deformation and annealing textures of surface layers of copper sheets cold-rolled under unlubricated condition

The texture of rolled sheets is known to vary with depth from the shear texture in the surface layer to the planestrain-compression texture in the center layer. This study has interpreted the deformation and annealing textures evolved in the surface layer of a four-layered-copper sheet cold-rolled by 93% reduction in thickness without lubrication at room temperature. The surface and center layers were separated from the cold-rolled four-layered copper sheet. The deformed surface layer was annealed for 1 h at 823 K. The deformation texture of the surface layer could be simulated by straining the {112} oriented fcc crystals by a true strain of 2.66 in the rolling direction at 0 ≤ |e 13/e 11| ≤ 1.4, where eij are the displacement gradients and the subscripts 1 and 3 represent the sheet rolling and sheet surface normal directions, respectively, using a visco-plastic self-consistent scheme. The annealing texture could be approximated by the simulated shear deformation orientations plus near the {001} orientation that was approximated by the recrystallization orientations calculated from the simulated deformation orientations. The recrystallization orientations were calculated by the strain-energy-release-maximization theory for the recrystallization texture evolution.

Asymmetric Dearomatization Catalysts

A new methodology based on the strain energy release maximization (SERM) theory and Avrami-type kinetics is introduced to predict the evolution of recrystallization texture in a non-grain oriented (NGO) electrical steel. The deformation orientation and the activated slip system of each orientation, which can be developed by cold rolling for a hot-rolled NGO electrical steel, were calculated using the finite element method and visco-plastic self-consistent model. Afterwards, the recrystallization orientations that can evolve from each deformation orientation were determined by the SERM theory, and their fraction over the annealing time was calculated based on the Avrami-type kinetic equation. As a result, this approach for the NGO electrical steel could successfully predict the formation of γ-fiber with strong {1 1 1}〈1 1 2〉 component during recrystallization, which was in good agreement with the experimental results.

Solvay files patent infringement lawsuit against Molycorp in the patents court of England and Wales

A new methodology based on the strain energy release maximization (SERM) theory and Avrami-type kinetics is introduced to predict the evolution of recrystallization texture in a non-grain oriented (NGO) electrical steel. The deformation orientation and the activated slip system of each orientation, which can be developed by cold rolling for a hot-rolled NGO electrical steel, were calculated using the finite element method and visco-plastic self-consistent model. Afterwards, the recrystallization orientations that can evolve from each deformation orientation were determined by the SERM theory, and their fraction over the annealing time was calculated based on the Avrami-type kinetic equation. As a result, this approach for the NGO electrical steel could successfully predict the formation of γ-fiber with strong {1 1 1}〈1 1 2〉 component during recrystallization, which was in good agreement with the experimental results.

Interrelation Between the Orientations of Deformation and Recrystallization in Hot Rolling of Anisotropic Electrical Steel

The method of orientation microscopy (EBSD) is used to study the interrelation between deformation and recrystallization orientations in the structure of hot-rolled strip plate for the production of electrical anisotropic steel. It is shown that the interrelation between the orientations of recrystallized and deformed grains is implemented through a set of special off-orientations formed between the principal deformation orientations.

Reverse bending effect on the texture, structure, and mechanical properties of sheet copper

The effect of reverse room-temperature bending on the crystallographic texture, metallographic structure, and mechanical properties of preliminarily rolled and annealed sheets of copper has been studied. It has been found that the type of the initial structure and the texture represented by the {001}〈100〉 recrystallization orientation, remains of the deformation texture {112}〈111〉, and twin orientations do not change; only the ratio of these orientations changes in the process of the reverse bending, which naturally leads to changes in the mechanical properties.

Evolution of crystallinity and of crystallographic orientation in isotactic polypropylene during rolling and heat treatment

The development of the crystallinity and of the crystallographic orientation of isotactic polypropylene during rolling deformation and subsequent heat treatment is studied. The experiments are conducted by using X-ray diffraction with an area detector. The evolution of crystallographic orientation is tracked by calculating the pole figures and by applying a quantitative 3D texture component fit method. The rolling orientation after a true strain of −1.5 mainly consists of the (0 1 0)[0 0 1], (1 3 0)[0 0 1], and [0 0 1]//RD fiber components (RD: rolling direction). The results reveal that the crystallinity drastically decreases during rolling. We suggest that decrystallization (disaggregation) is a deformation mechanism which takes place as a microscopic alternative to crystallographic intralamellar shear depending on the orientation of the lamellae relative to the imposed deformation tensor. Heat treatment after rolling leads to the recrystallization of amorphous material and to a strong enhancement of the fiber orientation component. The recrystallization orientation is explained in terms of an oriented nucleation mechanism where amorphous material aligns along existing crystalline lamellae blocks which prevailed during the preceding deformation.

Micro-Scale OIM Study on the Recrystallization Process of Cold Rolled α-Fiber Single Crystal

Recrystallization of cold rolled {211}&lt;011&gt; single crystal of 3.5%Si-Fe were investigated by electron back-scattered pattern (EBSP) technique in order to clarify the formation of {h,1,1}&lt;1/h, 1, 2&gt; fiber in recrystallization texture of steel with high cold rolling reduction. In the cold rolled sample, there exist shearband like substructures characterized by the orientation fluctuation with single &lt;011&gt; axis whereas their orientations are almost kept to the original orientation {211}&lt;011&gt; which belongs to a-fiber (RD//&lt;110&gt; fiber). In the recovery stage, the orientation fluctuations are enhanced and include fluctuations with another &lt;011&gt; axis. That is the fluctuations in recovery stage are not characterized by rotation relationship with single &lt;011&gt; axis. The recrystallization texture includes {100}&lt;012&gt; and {411}&lt;148&gt; as major orientations in {h,1,1}&lt;1/h, 1, 2&gt; fiber. Furthermore, there exists clear orientation relationship characterized by multiple rotations with &lt;011&gt; axes between the recrystallization orientations and the original one. Actually, orientations characterized by rotational relationships with &lt;211&gt; (=[110]+[101]) axis and &lt;111&gt; (=[110]+[101]+[011]) were observed. These results suggest that recrystallization from a-fiber is occurred as a result of the final enhanced stage of the fluctuations characterized by multiple rotations with &lt;011&gt; axes.

Development of Deformation and Recrystallization Orientations during Hot Rolling of Al-4.5Mg Alloy

Controlling the metallurgical structure during hot rolling of high magnesium-aluminum alloys is of essential importance in the production of sheet products, because hot rolling parameters significantly affect alloy recrystallization behavior. Developing the proper microstructure and grain texture in the hot band is necessary to ensure good mechanical properties and formability in the final product. In order to study the effects of high temperature deformation on the recrystallization behavior of Al-4.5 Mg, a designed laboratory hot rolling experiment was performed to investigate the interactions between hot rolling reduction, speed, and temperature. The evolution of microstructure and texture during hot rolling was examined using transmission electron microscopy (TEM) and orientation distribution functions (ODFs). The recrystallization behavior observed is explained in terms of the development of grain orientation during deformation in order to propose a recrystallization mechanism for this alloy system.

Kinematics of the Rockland Brook Fault, Nova Scotia: Implications for the interaction of the Meguma and Avalon terranes

The Cobequid-Chedabucto fault system of northern mainland Nova Scotia represents the surface expression of the Avalon-Meguma terrane boundary, but because it is exposed at high crustal levels in the Cobequid Highlands, the fault system provides little information as to the kinematic relationships of the two terranes in this area. In the eastern Cobequid Highlands, the Rockland Brook Fault (RBF) is exposed within the more deeply eroded highlands massif and juxtaposes units of widely varying ages and lithologies. Therefore, this fault is better suited to define the nature and timing of fault movement associated with Avalon-Meguma terrane interaction. In several large Carboniferous plutons along the length of the RBF, and in previously deformed Precambrian rocks, mylonitic foliation orientations are predominantly east-west trending and mineral lineations plunge southeast. Kinematic indicators such as minor fold vergence, porphyroclast systems, asymmetric boudins, shear-band fabrics, and preferred recrystallization orientations indicate dextral shear. These data are taken to infer that the central section of the RBF is dominated by dextral strike-slip motion. Transpression occurs locally where the RBF curves into restraining bends. Kinematic data in these bends indicate top to the northwest thrusting. At the easternmost extent of the RBF, high-level brittle normal faults predominate in the locally extensional environment. The timing of RBF movement is constrained only by the ca 360 Ma granite bodies which it deforms and by the Westphalian sedimentary rocks which are affected by only the latest stages of movement. These kinematic data are consistent with previously published kinematic models for the interaction of the southern margin of the Avalon Composite Terrane with the Meguma Terrane in mainland Nova Scotia. These models suggest that regional dextral shear was accompanied by localized components of transpressional thrusting, wrench tectonism, and small-scale sedimentary basin development during Devonian to Carboniferous terrane interaction.