Brass Texture Research Articles

Brass-texture induced grain structure evolution in room temperature rolled ODS copper

Currently, advanced ODS copper alloy is under study as a potential fusion material providing good mechanical properties. In this work, in order to develop a high performance ODS copper containing 0.5 wt% Y2O3 oxide particles, the effect of room temperature rolling and subsequent annealing on the grain structure evolution, texture development and tensile properties are studied using EBSD, TEM and tensile tests. Microstructure evolution studies show the grain structure coarsens by enhancing the Brass texture during increase of rolling reduction and a unique single crystal-like brass-texture deformed structure is achieved after 80% rolling reduction. We found the deformation mechanism of partial slip by a6〈211〉 dislocations facilitated by the pinning of a2〈101〉 perfect dislocations through fine oxide particles is responsible for formation of Brass texture during room temperature rolling. Furthermore, the recrystallization of ODS copper retards to high temperature of ~700 °C and shows a fine-grained microstructure with different orientations of Goss, Brass, S and Copper. Evaluation of microstructure-mechanical properties of the recrystallized samples expresses that the bimodal grain size distribution at 800 °C for 30 min offers a good tensile strength-ductility (UTS: 491 MPa, elt: 19%) at ambient temperature.

Effect of large strain cross rolling on microstructure and properties of Al−Li alloy plates with high magnesium content

Abstract Transmission electron microscopy (TEM), electron backscattered diffraction imaging (EBSD) and X-ray diffractometry were used to analyze the microstructure and texture characteristics of Al−9.8Mg−1.5Li−0.4Mn alloy cross-rolled and extruded plates, and the tensile properties and deep drawing performance were measured. The results show that the occurrence of dynamic recrystallization was promoted, the grains were refined and the preferred orientation of the recrystallized grains was improved by large strain cross rolling. Compared with CBA and CCB rolling methods, CBB rolling method significantly reduced the orientation density of the typical Brass texture {110}〈112〉 in the extruded plates. The orientation densities of Copper texture {112}〈111〉 and Brass texture {110}〈112〉 on the β orientation line in the CBB rolled plates were the lowest, and there were no typical texture features in the plates. Meanwhile, better deep drawing could be gained in the CBB rolled plates, and the mechanical properties of the 0°, 45° and 90° directions were basically the same. The tensile strength, yield strength and elongation at room temperature for the CBB rolled plates were 617 MPa, 523 MPa and over 20.1%, respectively. The deviation of the mechanical properties at different directions was less than 3%.

Effects of temperature and strain rate during hot rolling on microstructure and tensile properties of high-strength Al–Zn–Mg–Cu alloy

The effects of temperature and strain rate during hot rolling on the microstructure and tensile properties of high-strength Al–Zn–Mg–Cu alloy were investigated. Hot rolling was performed with controlled temperature (300°C, 350°C, 400°C) and strain rate (0.3/s, 2.0/s). Hot-rolled samples were prepared by solution heat treatment followed by T6 aging treatment. With the increase of the Z parameter calculated from the temperature and strain rate during hot rolling, the 0.2% proof stress after T6 treatment increased by up to 20 MPa at the surface region of the rolled sheets and by up to 8 MPa at the center region. This is because the average subgrain diameter became smaller as the Z parameter increased. In addition, the 0.2% proof stress of the center region of the rolled sheets was about 70 MPa higher than that of the surface region. At the center region, the orientation densities of Brass texture ({011}〈211〉), S texture ({123}〈634〉), and Cu texture ({112}〈111〉) were higher than that of the surface region. Therefore, the Taylor factor was higher at the center region than the surface region, and as a result, the 0.2% proof stress of the center region became high.

Microstructure and texture evolution in warm rolled API 5L X70 pipeline steel for sour service application

The evolution of microstructure and texture of API 5L X70 pipeline steel after warm rolling treatments has been studied using X-ray diffraction and electron backscatter diffraction (EBSD). Our investigations revealed that the microstructure after the rough rolling stage consist of coarse grained ferrite and bainite clusters, while the specimens finished rolled at 600 °C and 700 °C consist mainly of elongated ferrites and a well recrystallized polygonal shaped ferrite grains. EBSD investigations confirmed that dynamic recovery was dominant during the rough rolling stage; whereas a partial recrystallization and a well recrystallized structure were observed during finish rolling at 600 °C and 700 °C respectively. X-ray macro-texture measurement showed that the intensity of the desired γ-fiber texture is dependent on the finish rolling temperature. The finish rolling treatments lowered the fractions of the Goss, Brass, S and Copper texture components. However, higher fractions of the Goss {001}〈100〉, brass ({110}〈112〉), S ({123}〈634〉) and Copper ({112}〈111〉) were observed in steels rolled at 600 °C finish rolling temperature. Strong texture inhomogeneity during warm rolling was observed. The γ-fiber is seen to be better formed at the mid thickness compared to the surface. Most grains at the mid thickness were oriented in the {111}‖ND and {001}‖ND at both finish rolling temperatures. The finish rolling temperature played a key role in the development of texture such that the recrystallization of grains in steel finish rolled at 700 °C favoured the development of the γ-fiber texture.

Achieving Grain Refinement and Related Mechanical Property Improvement of an Al-Zn-Mg-Cu Alloy Through Severe Plastic Deformation

Microstructural features and mechanical properties of an Al-Zn-Mg-Cu alloy processed by equal-channel angular pressing (ECAP) have been investigated. The equivalent plastic strain obtained from the simulation agrees well with that from the analytical calculation in a way that both increase with an increase in deformation, but the strain distribution is non-uniform, appearing as a strain gradient along the norm direction. Microstructure investigation shows that grain refinement is achieved in frequency of low-angle grain boundaries fabricated by ECAP. The pole density is reduced by ECAP, during which the Brass and Goss type textures are introduced. TEM results show chain-like recrystallized grains formed at the grain boundaries and broken second-phase particles come into being due to the heavy shear force. After ECAP, the hardness and strength increase significantly while the elongation is reduced. Besides, an extreme strengthening is confirmed because of the balance between dynamic hardening and softening. The microstructure evolution mechanism is revealed in terms of grain refinement, precipitate phase breakage and texture evolution.

Microstructure and texture based analysis of forming behavior and deformation mechanism of AA1050 sheet during Single Point Incremental Forming

In case of Single Point Incremental Forming (SPIF) process, the deformation mechanism, absence of material localization prior to fracture and enhanced formability are still not satisfactorily explained. The objective of this work is to understand the sheet deformation characteristics, forming behavior, and dominant deformation mechanism of SPIF process. Process deformation characteristics such as dimensional accuracy, thickness distribution, true surface strain, von Mises stress and equivalent plastic strain, evolved at different forming stages, were evaluated through experimental investigation and Finite Element Analysis (FEA) of the formed parts. The evolved microstructural features for different stages and modes of strains have been analyzed by Electron Back Scatter Diffraction (EBSD) and X-Ray Diffraction (XRD) techniques. Analysis has also been carried out to identify the reason of typical failure under biaxial strain mode. An abundance of {001} <100> Cube texture component in the early forming stage indicates the occurrence of dominant shearing in this stage. The intermediate forming stage develops dominant {011} <111 > P texture component, which remains intact up to the final forming stage. This shows that Particle Stimulated Nucleation (PSN) has taken place due to excessive strains occurring in the sheet material during SPIF, causing grain refinement and shear band formation, and simulating kind of recovery or recrystallization process. Enhanced formability in SPIF can be attributed to the depletion of {001} <100> Cube texture, and development of {011} <111 > P texture and {011} <211> Brass texture component with the progression of SPIF.

Effect of cross-rolling on microstructure and texture evolution and tensile behavior of aluminium-copper-lithium (AA2195) alloy

The evolution of microstructure and crystallographic texture during thermo-mechanical processing and their effect on tensile behavior of Al-Cu-Li (AA2195) alloy were investigated in the present work. The initial hot rolled sheets were cold rolled by unidirectional rolling and cross-rolling. These sheets were annealed and imparted T6 (solution treatment + water quenching + aging) temper. Uni-directionally rolled samples exhibited typical copper texture which subsequently transformed to cube component after thermal treatment whereas, the cross-rolled sample exhibited brass texture which subsequently weakened upon thermal treatment. The difference in the precipitation characteristics resulted in transition from anisotropic to isotropic strength in cross rolled samples in heat treated condition. The strength anisotropy has been explained based on the average precipitation strengthening factor and accommodation tensor.

Static recrystallization texture and microstructure evolution of copper-manganese alloy pre-deformed by unidirectional rolling

Recrystallization often leads to dramatic texture changes whose underlining mechanisms remain unclear. In this study, copper-manganese alloys were subjected to unidirectional rolling and annealing. The texture of the samples was evaluated by x-ray analysis. Electron back scattering diffraction was used to investigate the local orientations and annealing twins. The origin of particular orientations of recrystallization texture were determined by comparing the macrotextures. Results showed that the 50% rolled samples were fully recrystallized after annealing at 450 °C for 1 h, and the 77% and 95% cold-rolled samples were fully recrystallized after annealing for 0.5 h. The rolling deformation and annealing time influenced the fraction ratio of twin boundaries in the recrystallized grains. After isothermal annealing, the 50% and 77% rolled samples still had strong Brass texture, whereas the 95% rolled samples mainly exhibited Cube texture and Cube-RD texture.

Effect of cold-rolling on microstructure, texture and mechanical properties of an equiatomic FeCrCuMnNi high entropy alloy

In the present study, the effect of cold-rolling on the microstructural evolution, texture development and mechanical properties of an equiatomic FeCrCuMnNi dual phase high entropy alloy (HEA) was investigated. The homogenized HEA was cold-rolled at different strain levels. The material properties were evaluated by employing XRD, SEM-EBSD, tensile, and hardness tests. No phase transformations were observed during rolling. The FCC phase exhibited high local deformation if compared to the BCC one. As a consequence, a marked elongation along the rolling direction was revealed for the FCC phase. A strong texture variation as well as the formation of Brass and shear texture components were observed in the alloy for different deformation levels. By increasing the deformation, the material's strength increased; the elongation decreased due to formation of new grain boundaries and to the increasing in the dislocation density. Rolling led to the modification of the fracture mechanisms, revealing a shift from a ductile behavior to a partially brittle one.

On the correlation of shear band formation and texture evolution in α-brass during accumulative roll bonding

We studied the microstructural evolution of the low stacking fault energy α-brass alloy CuZn15 during accumulative roll bonding (ARB). Most notably, the typical brass-type texture was clearly observed after four ARB passes (approx. 93.8% total thickness reduction), before significant shear localization set in. This observation contradicts the widely accepted idea that shear band formation is a necessary prerequisite for the development of the brass type texture, indicating that the two phenomena, shear banding and development of the brass texture, are only correlated in ARB, and that their order of appearance can be switched depending on experimental parameters.

Deciphering the Possible Role of Strain Path on the Evolution of Microstructure, Texture, and Magnetic Properties in a Fe-Cr-Ni Alloy

In the present work, the influence of strain path on the evolution of microstructure, crystallographic texture, and magnetic properties of a two-phase Fe-Cr-Ni alloy was investigated. The Fe-Cr-Ni alloy had nearly equal proportion of austenite and ferrite and was cold rolled up to a true strain of 1.6 (thickness reduction) using two different strain paths—unidirectional rolling and multi-step cross rolling. The microstructures were characterized by scanning electron microscopy (SEM) and electron backscattered diffraction (EBSD), while crystallographic textures were determined using X-ray diffraction. For magnetic characterization, B-H loops and M-H curves were measured and magnetic force microscopy was performed. After unidirectional rolling, ferrite showed the presence of strong α-fiber (rolling direction, RD//〈110〉) and austenite showed strong brass type texture (consisting of Brass (Bs) ({110}〈112〉), Goss ({110}〈001〉), and S ({123}〈634〉)). After multi-step cross rolling, strong rotated cube ({100}〈110〉) was developed in ferrite, while austenite showed ND (normal direction) rotated brass (~ 10 deg) texture. The strain-induced martensite (SIM) was found to be higher in unidirectionally rolled samples than multi-step cross-rolled samples. The coherently diffracting domain size, micro-strain, coercivity, and core loss also showed a strong correlation with strain and strain path. More strain was partitioned into austenite than ferrite during deformation (unidirectional as well as cross rolling). Further, the strain partitioning (in both austenite and ferrite) was found to be higher in unidirectionally rolled samples.

Misorientation Distribution Function of Crystals

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Coincidence site lattice boundary mechanism for the preferred growth of Goss and Cube grains during annealing in an Al-Cu-Mg alloy

The formation mechanism of recrystallized textures in an Al-Cu-Mg alloy was investigated by means of three dimensional orientation distribution functions (ODFs) and in-situ electron back-scattered diffraction (EBSD). The results showed that in the hot-rolled alloy with a very sharp Brass texture but weak Copper and S orientations, both Goss and Cube grains were recrystallized out of parent Brass matrix. In-situ EBSD analysis revealed that characteristic boundary between Brass and Goss grains to be Σ9, while that between Brass and Cube grains to be Σ5. Frequency of Σ9 and Σ5 boundaries increased quickly at early stage and then reduced gradually with the process of recrystallization. Annealing at a higher temperature (320 °C) was found to be beneficial for the formation of Σ9 boundary, while at lower one (300 °C), Σ5 boundary became dominant. Besides, with temperature decreasing from 320 to 300 °C, the mobility of Σ9 boundaries was greatly degraded, but relatively, Σ5 boundaries still behaved highly mobile. Principally, the preferred growth of recrystallized Goss and Cube grains was respectively attributed to the high mobility of Σ9 and Σ5 boundaries with high index planes that the square sum of plane index was larger than 3.

Effects of Changing Hot Rolling Direction on Microstructure, Texture and Mechanical Properties of Cu-2.7Be Sheets

A hot rolling scheme (cross-rolling and unidirectional rolling) was adopted to process Cu-2.7Be sheets used as multiplier dynodes in photomultiplier. The effects of changing rolling direction on microstructure, texture and mechanical properties were studied by a combination of XRD, EBSD and TEM. It was found that higher copper-type texture and lower brass texture intensity were obtained in the ultimately cross-rolling (CR) sheet compared with the unidirectional rolling (UR) sheet.The EBSD results indicated that the grain orientation from mainly $$\left\langle {101} \right\rangle$$ for UR sample turns to random for CR sample. Great enhancements in YS and UTS after unidirectional rolling were attributed to the massive and polygonal γ precipitates. The CR sample exhibited lower anisotropy, because of the increase of S and γ precipitates with spherical and tiny shape.

Development of Goss texture in Al–0.3%Cu annealed after heavy rolling

The evolution of the microstructure and texture during annealing has been studied in the center layer of 95% cold rolled Al–0.3%Cu with a large initial grain size. The cold-rolled condition is characterized by a strong Brass texture component and a deformed microstructure comprising lamellar structures intersected by a large number of shear bands. Recrystallization and precipitation take place during annealing at 200 °C, and a strong Goss texture develops. In the beginning of recrystallization, Goss oriented grains nucleate preferentially at the shear bands. At a later stage of recrystallization, new Goss nuclei can appear in regions where lamellae of the dominant Brass component are interspersed with Goss-oriented subgrains. When recrystallization is almost complete, recrystallized Goss-oriented grains grow into grains of other orientations, which results in a rapid increase in the average grain size of Goss-oriented grains and strengthening of the Goss texture. As a result, new low angle boundaries are formed between Goss-oriented grains in this strongly textured material.

Effect of S phase characteristics on the formation of recrystallization textures of an Al-Cu-Mg alloy

The effect of S(Al2CuMg) phase size on the formation of texture in an Al-Cu-Mg alloy during annealing has been systemically examined using three dimensional Orientation Distribution Functions (ODFs), Electron Back Scattered Diffraction (EBSD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The results showed that in the region of sheet with the uniform fine S phase precipitates (1–4.5 μm in size), Brass texture mainly transformed into Goss texture after annealing at 320 °C for 4 h. The preferred growth of Goss texture was attributed to the high mobility of Σ9 boundary between Brass and Goss grain. However, in the region of sheet containing intense coarse S phase precipitates (1–8 μm), Brass texture mainly transformed into r-Goss texture after the same annealing condition. The large S phases with size of 4.5–8 μm, were suggested to be responsible for the formation of r-Goss texture. Also, due to the particle stimulated nucleation (PSN) effect caused by these large S phases (4.5–8 μm), the boundaries between Brass and r-Goss grains were non-CSL boundaries. Instead, the preferred growth of r-Goss grain was ascribed to the higher mobility of r-Goss grain boundary with misorientation angle of 26–43°, than that of low (<26°) and high (>43°) angle boundaries.

Effects of Solid Solution and Aging Treatment on Texture Evolution and Properties of Cu-Ni-Si Alloy

The relationship between textures and properties of Cu-Ni-Si alloys was analyzed in this paper. The texture evolution of high strength and high elasticity Cu-Ni-Si alloy in different cold rolling and heat treatment processes was researched by the fiber analysis. And the electrical conductivity and tensile strength in different directions of the Cu-Ni-Si alloy were measured. The results showed that there were mainly Brass texture B{011}&lt;211&gt;，Gauss texture G {011}&lt;100&gt; and Copper texture C {211}&lt;111&gt; in the cold-rolled Cu-Ni-Si alloy. With the increase of cold deformation, the Copper texture was weakening, while the Gauss texture and Brass texture increased. When the deformation was 65%, there was almost no Copper texture in the alloy, and only Gauss and Brass texture exist. After the solid solution and aging process, both the Gauss and Brass texture were weakening, while the S texture {123}&lt;624&gt; increased greatly. After 4 hours aging the conductivity was up to 42.7% IACS. And the tensile strength of different directions is 745.5MPa (0°direction,RD), 684.5MPa (90°direction,TD) and 653.5MPa (45°direction) respectively. Based on the above results, maximum Schmid factor of different textures in different directions and the Index of Plane Anisotropy (IPA) were been analyzed.

Electron Backscatter Diffraction Analysis of the Microstructure Fineness in Pure Copper Under Torsional Deformation

Torsional deformation is regarded a promising deformation procedure to prepare the gradient structural materials. Pure copper was subjected to large plastic strains in torsion. Electron backscatter diffraction analysis was used to explore the microstructure evolution. The observations demonstrate that both high-angle grain boundaries and misorientation increase with strain. The grains finer and more homogeneous. In addition, the microstructure within the shear band demonstrates a distinct preferred orientation. The crystal direction is parallel to the shear direction, and the crystal {111} inclines to the plane shear surface. A torsion-induced bar specimen includes a {011} brass texture, {011} Gaussian texture, and stronger {112} copper texture.

Ultrafine microstructure and texture evolution of aluminum foil by asymmetric rolling

AA1060 aluminum foil was rolled from 4 mm to 20 μm by asymmetric rolling without intermediate annealing. The microstructures and textures were investigated. The original coarse grains with an average grain size of 60 μm were refined to fine equiaxed grains with an average grain size of about 500 nm with mainly large grain boundaries. During the rolling, the intensities of copper texture C-{112} and brass texture B-{011} gradually increased, and most crystallites aggregated along the β and τ orientation lines. The orientation intensity reached the maximum value 26 when the foil was rolled to 500 μm, but significantly decreased to 16 when the thickness became 20 μm, and the texture mainly consisted of a rotation cubic texture RC-{100} . With the combined forces including drawing, compressing and shearing, severe plastic deformation was obtained during the asymmetric rolling, promoting dynamic recrystallization at room temperature. Because of a combined force in the deformation zone and shear force along the normal direction, dynamic recrystallization occurs during the asymmetric rolling; therefore, the average grain size is significantly refined. The texture intensity of ultrathin strip first increases, i.e., work hardening, and then decreases mainly because of dynamic recrystallization.

Forming behavior and microstructural evolution during single point incremental forming process of AA-6061 aluminum alloy sheet

AA-6061 aluminum alloy is extensively used in automobile and aerospace industries due to its high strength-to-weight ratio. However, this material shows limited formability in age-hardened condition at room temperature. Therefore, a new forming method known as single point incremental forming (SPIF) to deform the sheet was adopted. The SPIF experiments and finite element method (FEM) simulation were performed to form the sheet into the desired conical shape. Digital image correlation (DIC) method was used to measure the major and minor strains post deformation experimentally, and results were compared with FEM results. Detailed microstructural study was performed to understand the deformation behavior of AA-6061 aluminum alloy sheets during SPIF. It is observed that plastic anisotropy has strong effect on microstructure and texture development in different directions of AA-6061 alloy sheet during SPIF. It is also observed that volume fraction of goss and S texture components remains stable, whereas volume fraction of cube and brass texture changes significantly.