Copper-type Texture Research Articles

An investigation to microstructural and texture evolution during the cold rolling of Al0.3CoCrFeNi high entropy alloy

In the present study, Al0.3CoCrFeNi high entropy alloy (HEA) was subjected to thickness reductions through cold rolling process in order to thoroughly investigate the evolution of microstructure and deformation texture. Important aspects of deformed microstructures such as the formation of twinning bundles and shear bands in the specimens were monitored. The evolution of texture during the cold rolling process was measured by X-Ray Diffraction (XRD) and Electron Back Scatter Diffraction (EBSD) technique which revealed the formation of Copper type texture at the initial stages of rolling due to slip deformation mechanism. Originated from twinning and followed by shear banding, the texture was subsequently developed toward predominantly Brass type. Microstructural features and texture evolution behavior of the investigated single phase FCC alloy was attributed to its low SFE level. Visco Plastic Self Consistent (VPSC) technique was coupled in the research to simulate the material behavior and to examine the contribution of slip and twinning systems. Benefiting VPSC justifications, the texture transition from Copper type to Brass type was related to lower CRSS value of slip in comparison to twinning at the small strains which was then grows faster at the later stages of rolling facilitating the onset of twinning and providing the texture transition basement.

Tailoring the microstructure and mechanical properties of Cu–Fe alloy by varying the rolling path and rolling temperature

Cu–Fe alloys are expected to be extensively used in electronics, transportation and machinery industries due to the extraordinary mechanical properties and functional properties. To optimize rolling process and the final properties of Cu–Fe plates. The effect of rolling path, rolling temperature and thickness reduction on microstructure evolution, mechanical and electrical properties of Cu–Fe alloy are carefully investigated. The results shown that the thickness reduction has a significant effect on mechanical properties of Cu–Fe alloy. The yield strength of Cu–Fe plates with 20% thickness reduction is more than 2 times higher than that of homogenized ingot. While the yield strength increases gradually as further increasing the thickness reduction. Rolling temperature is an important parameter determining the strength-ductility balance. The strength of plate rolled with 80% thickness reduction at 400 °C is similar to that of the plates in cold-rolled state, and the ductility is higher than that for the plates in the cold-rolled state. Further investigation reveals that the formation of heterogeneous structure characterized with recrystallized-fine grains embedded in deformed-coarse grains is responsible for the observed extraordinary mechanical properties. Rolling path could also affect the microstructure evolution and formability of the plates. For plate rolled with route 1 (unidirectional rolling), a stronger Copper-type texture with two Brass-type textures are observed. For plate rolled with route 2, where the rolled plate is rotated to 90° with respect to previous rolling direction between adjacent rolling passes, only Brass-type texture is generated. A rolling-path dependent edge-crack behavior is observed during rolling. Edge cracks are generated during rolling with route 2, while the edge cracks are not observed for plates rolled with route 1. Factors affecting the edge-cracks behavior are also discussed.

Microstructure, texture and mechanical properties of Al–Zn–Mg–Zr cylindrical part with thin-wall and high-rib formed by integral-accuracy-extrusion

The complex section cylindrical part with thin-wall and high-rib was obtained through integral-accuracy-extrusion, and the microstructure evolution, recrystallization behavior, texture configuration and strengthening and toughening mechanism were investigated. Samples of different positions all exhibit the microstructure of predominant elongated grains along extrusion direction (ED) surrounded by fine equiaxed grains, but the width of elongated grains in the rib is higher than that in the thin-wall. Except for particle-stimulated nucleation (PSN) mechanism due to the MgZn2, the dominant recrystallization mechanism of all samples should be discontinuous dynamic recrystallization (DDRX), and the parent grains with the orientation of (001)//ED are more susceptible to recrystallization than other orientations. Additionally, more prone to continuous dynamic recrystallization (CDRX) results in a higher recrystallization fraction and a lesser average grain size in the thin-wall. Samples in the rib are dominated by strong copper-type texture, showing the feature of deformation texture; as for sample in the thin-wall, a high strength of Cube texture is displayed. The ultimate tensile strength (UTS) of the sample in the rib is 20 MPa higher than that in the thin-wall, which is mainly attributed to texture strengthening caused by hard orientation grains with smaller Schmid factor (SF), but the elongation of sample in the thin-wall is 30% higher than the rib (15.1% vs 11.6%), showing a superior plasticity, which is related to higher SF, higher recrystallization fraction and more homogeneous microstructure. This research will theoretically guide the manufacture of high-performance complex section Al–Zn–Mg–Zr cylindrical part with thin-wall and high-rib.

Microstructure and texture evolution of pure nickel during cryorolling and subsequent annealing

The microstructure and texture evolution of pure nickel sheets during cryorolling and subsequent short-time low-temperature annealing were analyzed by electron backscatter diffraction technique. Results show that the content of typical texture of brass, copper, S, cube, and Goss texture is no significant change during cryorolling with a reduction of 40%. When the reduction reaches 60%, it begins to significantly increase, and when the reduction reaches 80%, it exhibits a copper type texture. However, when the reduction is 20%, the fiber texture of <110>//normal direction (ND) orientation begins to significantly increase, which was mainly caused by dislocation slip during cryorolling. During low temperature and short time annealing, the content of typical textures decreases except S texture, and the grain changes mainly occur in grains other than <110>//ND orientation which is due to the rich substructure and high dislocation density formed in the cryorolling process leading to rapid response to annealing.

Experimental analysis of deformation texture evolutions in pure Cu, Cu-37Zn, Al-6Mg, and −8Mg alloys at cold-rolling processes

Generally, two types of deformation textures of copper-type and brass-type textures are evolved in face-centered cubic (FCC) metals. During deformation, dislocation motion determines which texture will be dominant. The copper-type texture is formed in metals of high stacking fault energy by cross-slip of dislocations and subsequent dislocation cell formation. On the other hand, deformation twinning involves the brass-type texture evolution, whereas some exceptions, such as Al-Mg alloys, also have been reported. This study examined deformation texture evolutions in four cold-rolled FCC alloys of pure Cu, Brass (Cu-37Zn), Al-6Mg, and Al-8Mg alloys. Electron backscattered diffraction and X-ray line profile analysis methods investigated the deformation texture evolution. Three different strains of 0.25, 0.45, and 0.63 were applied to observe the strain effect on texture evolution. In pure Cu, the copper-type texture is developed, as commonly known. The brass-type texture is developed in Brass and Al-Mg alloys. More reduction ratios in those alloys lead to the copper-type texture strengthening in pure Cu, whereas stronger brass-type texture is shown in Brass and Al-Mg alloys by applying more reduction. While the brass-type texture evolution in Brass can be illustrated by deformation twinning, deformation twins are absent in deformed Al-Mg alloys despite their evident brass-type texture formation. Instead, the short-range ordering (SRO) mechanism can explain the brass-texture evolution in Al-Mg alloys. Planar slips by the high Mg content of Al alloys strengthen the rotated Goss orientation with brass-type texture evolution after cold-rolling processes of those alloys.

Effects of dislocation slip behaviour and second-phase particles on hot rolled texture of an Al-Cu-Mg alloy with a high Cu/Mg ratio

Microstructure and texture development of Al–Cu–Mg alloy with a high Cu/Mg ratio were investigated during homogenisation and hot rolling by using OM, SEM, DSC, XRD and TEM. The results showed that the Brass texture intensity increased by 2.4 times after hot rolling (90% rolling reduction), when the proportion of the second-phase particles in an area fraction and average particle size decreased from 1.32% to 0.24% and from 7.49 to 5.71 µm before hot rolling, respectively. Large particles inhibited the activation of the {111}< 110 > slip system, which led to a decrease in texture intensity. When the reduction increased, the following activated slip systems and located area of slip traces were obtained: {111}< 110 > (at grain boundaries, 35% rolling reduction), {111} + {100}< 110 > (at local area of grains, 65% rolling reduction), and {111} + {110}< 110 > (in most grains, 90% rolling reduction). In addition, the amount of the slip system corresponding slip planes increased as the spacing of the slip traces per 200 nm gradually decreased, which helped enhance the intensities of Brass- and Copper-type textures.

A crystal plasticity investigation on the influence of orientation relationships on texture evolution during rolling in fcc/bcc two phase materials

In two phase materials like duplex stainless steels that contain both the phases in nearly equal proportions, the crystallographic texture in the phases is related by special orientation relationship (OR). Most of the studies related to ORs are focused on characterising the type of ORs due to phase transformations and recrystallisation. However, very little is known about the stability of ORs and their role in the texture evolution during deformation. In this work, we present a detailed study on the role of ORs in the texture evolution during rolling in fcc/bcc two phase materials. Three different ORs; Bain, Kurdjumov–Sachs, Nishiyama–Wassermann and two different parent phases; fcc and bcc are considered. Using three-dimensional representative volume element (RVE) based crystal plasticity fast Fourier simulations, we report that the final textures depend strongly on the initial parent phase textures and the existence of an OR, and is independent of the type of the OR. A copper type texture is observed in the fcc phase, when the parent phase is bcc with cube texture. However, a brass type texture is observed when the parent phase is bcc with rotated cube texture. A detailed investigation using a series of bicrystal studies further revealed that even within an OR, the type of Bain variant plays a vital role in the overall texture evolution. It is also observed that there is no marked impact of the initial CRSS ratios and strain hardening on final textures of both the parent and child phases.

Evolution of mechanical properties, microstructure and texture and of various brass alloys processed by multi-directional forging

This study investigated mechanical properties and texture evolution of Cu-xZn alloys (x = 5, 15, 20, 30) processed by multi-directional forging (MDF) up to 6 passes at ambient temperature. Mechanical properties were examined via shear punch and hardness tests. Optical microscopy and high-resolution scanning electron microscopy (HR-SEM), equipped with electron backscattered diffraction (EBSD) detector were also utilized to characterize the detailed microstructures and texture evolutions. The MDFed Cu-xZn alloys after 6 passes showed superior mechanical properties without the reduction of electrical conductivity. Hardness, ultimate shear strength and shear yield strength of Cu-30Zn alloy improved by 213%, 83% and 85%, respectively after 6 passes of MDF. Enhancement of mechanical properties can be attributed to grain refinement. The MDFed Cu-5Zn alloy presented a predominantly Copper-type texture due to the higher activity of shear bands. By increasing Zn to Cu-15Zn and Cu-20Zn, Brass and Goss texture components were observed. Finally, Cu-30Zn alloy possessed a Brass texture which could be attributed to a higher amount of twinings.

Strain rate effects on microstructure and texture evolution in cold-sheared Al-6 Mg alloys during low-temperature annealing

This study examined the effects of the strain rate on the texture evolution of Al-6Mg alloys over one hour of annealing at 300 °C. Three different strain rates of 0.1 s−1, 1 s−1, and 10 s−1 were applied to the samples using a torsion tester. Considerable grain growth was observed in the 0.1 s−1 cold-sheared sample during one hour of annealing. The growth of B/B- and C-oriented grains can explain the grain coarsening behavior. The conventional grain growth, nucleation, and subsequent grain growth, plausibly describe the grain size evolution of those 1 s−1 and 10 s−1 cold-sheared samples during annealing. A textural transition from brass-type to copper-type was evident during the annealing process of the 1 s−1 cold-sheared sample. On the other hand, the brass-type texture bias in the 10 s−1 cold-sheared sample increased gradually over one hour of annealing. The copper-type texture generally evolved under the 0.1 s−1 cold-sheared condition. Generally, the misorientation indices (= M-index) of all three cold-sheared samples were decreased by extending the annealing time. A smaller M-index indicates stronger texture anisotropy. Although the M-index was higher in the 0.1 s−1 and 10 s−1 cold-sheared samples than the 1 s−1 sample throughout the annealing process, the M-index of the 0.1 s−1 sample eventually became the lowest among the three conditions under the fully annealed condition.

Effect of cold rolling on microstructure and texture evolution in strip casting Fe-36%Ni invar alloy foil

A new processing route including strip casting, cold rolling and annealing was proposed to manufacture the 0.05 mm-thick Fe-36%Ni invar alloy foil. The as-cast strip had coarse columnar austenite grains and pronounced {100}<0vw>fiber texture due to the high melt superheat during strip casting. The severe cold rolling in one-stage cold rolling route led to inhomogeneous deformed microstructures and strong copper-type textures. The striking features were the absence of Cube texture ({001}<100>) in the 0.05 mm-thick cold rolled strip and the appearance of {001}<310>texture after annealing, differing from the results that sharp Cube texture was normally the unique annealing texture in case of severe cold rolling. By contrast, two-stage cold rolling route led to the sharp Cube texture after final annealing even the cold rolling reduction was as high as 92.9%. The different microstructures prior to final cold rolling may be responsible for the evolution of Cube and {001}<310>texture in various routes.

Influence of Mg Content on Texture Development during Hot Plain-Strain Deformation of Aluminum Alloys

The study addresses the effect of magnesium and other alloying elements on rolling “β-fiber” texture formation during hot deformation of aluminum alloys. For the study, flat cast ingots from three aluminum alloys with variable magnesium content were deformed in a Gleeble testing unit with different parameters of thermomechanical treatment. Immediately after completion of deformation, the samples were quenched using an automatic cooling system and the microstructure and crystalline texture was analyzed by optical microscopy and X-ray analysis. The analysis demonstrated that an increase in alloying components, magnesium in particular, leads to an increase in brass-type texture and a decrease in S and copper-type texture. The reason was that the simulation of the deformation texture development revealed a great contribution of impurity atoms rather than the decrease in stacking fault energy.

Severe warm-rolling mediated microstructure and texture of equiatomic CoCrFeMnNi high entropy alloy: A comparison with cold-rolling

The effect of severe warm-rolling on the microstructure and texture development in FCC equiatomic CoCrFeMnNi HEA was investigated in the present work. For this purpose, the HEA was warm-rolled to 90% reduction in thickness at 600 °C and annealed for 1 h at temperatures up to 1200 °C. To highlight the effect of warm-rolling, a critical comparison was made with similarly deformed and annealed cold-rolled HEA. The warm-rolled HEA showed an ultrafine lamellar microstructure, which was, however, significantly coarser than the cold-rolled HEA. The significantly coarser microstructure in the warm-rolled HEA could be attributed to the dynamic annihilation of dislocations during deformation. Warm-rolled HEA showed a pure metal or copper type texture instead of a predominantly brass type texture in the cold-rolled HEA. The stark differences in the deformation texture could be attributed to the increase in the SFE at the temperature of warm-rolling, which promoted more homogeneous deformation by dislocation slip over twin mediated deformation and extensive shear band formation. The lower stored energy and coarser deformation structure of the warm-rolled HEA resulted in higher recrystallization temperature, and consistently larger recrystallized grain size than the cold-rolled HEA. Annealing also resulted in the weakening of the recrystallization texture owing to the absence of strong preferential nucleation or growth. The HEA warm-rolled and annealed at 750 °C resulted in a fine-grained, completely recrystallized microstructure with the optimum strength-ductility combination. The present results revealed that warm-rolling could be effectively used as a processing route for tailoring microstructure and properties of CoCrFeMnNi HEA.

Micro-mechanism of evolution of microstructure and texture in Ni-Fe alloys

A comprehensive investigation was carried out to explore the micro-mechanisms associated with the evolution of deformation microstructure and texture in Ni-Fe alloys during rolling. X-ray diffraction, electron back-scatter diffraction (EBSD) and Mössbauer spectroscopy as well as simulation methods involving crystal plasticity and molecular dynamics simulations were used to explore the mechanism of evolution. Pure Ni, Ni20wt.%Fe and Ni40wt.%Fe were rolled to true strain 3.0, following two different strain paths. Unidirectionally rolled Ni20wt.%Fe and Ni40wt.%Fe alloys show copper type texture, similar to that of pure Ni. By contrast, the cross rolled samples show the development of α-fibre along with A {110}<111> and cube {100}<001> orientations. Both Ni20Fe and Ni40Fe exhibit extensive shear banding in UDR as well as CR conditions, unlike pure Ni, which has been attributed to the appearance of two short-range ordered phases, Ni3Fe and NiFe. In case of UDR, the nature of shear banding is different in Ni20Fe and Ni40Fe alloys, while after CR both the alloys show similar microstructures displaying higher fraction of shear banding compared to UDR. Simulation results have indicated that larger number of slip systems are activated in case of CR compared to the UDR samples that leads to the formation of a weaker texture in the former. Some strain free grains have been observed near the shear banded regions, indicating that an extended recovery mechanism could be operative in Ni20Fe and Ni40Fe. This phenomenon was more pronounced when the fraction of shear bands was more.

Texture transition in Al–Mg alloys: effect of magnesium

ABSTRACT The evolution of deformation texture and microstructure in commercially pure Al (cp-Al) and two Al–Mg alloys (Al–4Mg and Al–6Mg) during cold rolling to a very large strain (true strain εt ≈ 3.9) was investigated. The development of deformation texture in cp-Al, after rolling, can be considered as pure metal or Copper-type, which is characterised mainly by the presence of Cu {112}<111>, Bs {110}<112> and S {123}<634> components. The deformation microstructure clearly indicates that deformation mechanism in this case remains slip dominated throughout the deformation range. In the Al–4Mg alloy, the initial slip mode of deformation is finally taken over by mechanism involving both slip and Copper-type shear bands, at higher deformation levels. In contrast, in the Al–6Mg alloy, the slip and twin mode of deformation in the initial stage is replaced by slip and Brass-type shear bands at higher deformation levels. Although a Copper-type deformation texture forms in the two Al–Mg alloys at the initial stage of deformation, there is a significant increase in the intensity of the Bs component and a noticeable decrease in the intensity of the Cu component at higher levels of deformation, particularly in the Al–6Mg alloy. This phenomenon indicates the possibility of transition of the deformation texture from Cu-type to Bs-type, which is concurrent with the addition of Mg. Using visco-plastic self-consistent modelling, the evolution of deformation texture could be simulated for all three materials.

Effect of the Mg contents on the annealing mechanism and shear texture of Al–Mg alloys

As conventional Al–Mg alloys have a high stacking fault energy (SFE), a copper type texture evolves when it is deformed and annealed at ambient temperatures. Generally, the SFE decreases as the Mg content increases. If the SFE decreases sufficiently, the microstructure texture can change from copper to brass type. To achieve good formability with an optimal microstructure texture, severe plastic deformation (SPD) processes have been studied, and these processes mainly have shear deformation mode. As a type of SPD test, a torsion test is a method to obtain data for shear deformed materials. In this study, the effects of the Mg content on the evolution of shear and annealing textures of Al–Mg alloys were investigated using torsion tests. Al–6Mg and Al–9Mg alloys were deformed to a strain of 0.35 at a strain rate of 0.1 s−1 at room temperature. After the materials were torsioned, an annealing process was conducted at 300 °C for 0–60 min for the deformed specimens. The electron backscattered diffraction technique was used to evaluate the microstructural texture of the samples after the suggested steps. As the Mg content increases under the same processing condition, a transition from copper to brass type was observed. A high Mg content resulted in an increase in stored energy. The variation in stored energy is related directly to the evolution of the annealing texture and its mechanism.

Formation of Recrystallization Cube Texture in Highly Rolled Ni–9.3 at % W

In this work the formation of strong recrystallization cube texture in heavily rolled Ni–9.3 at % W has been studied. During the cold rolling (also known as recovery-rolling) process the deformation texture of Ni–9.3 at % W alloy (further notated as Ni9W) transforms to Copper-type rolling texture, and after annealing, a sharp cube texture is generated. It is remarkably strong recrystallization cube texture, as high as 93 vol %, in metallic materials with low stacking fault energy. The formation mechanism of the cube texture is adopted for the rapid recovery of cube nuclei at the early stage of recrystallization as well as fast migration rate of high angle boundaries between cube grains and deformed microstructure at high temperature. Considering the cold rolling texture of Ni9W, oriented nucleation seems to play more important role in the cube texture formation process. In this article, the relationship between the deformation texture and recrystallization cube texture is discussed.

Uncharacteristic evolution of copper type texture in the presence of shearable precipitates

Abstract In the present work, development of rolling texture in the presence of shearable precipitates is analyzed using age hardenable aluminum magnesium silicon alloy (AA 6061) and aluminum-copper-lithium alloy (AA 2195). A characteristic Brass type texture evolves upon rolling of AA 6061 alloy containing β’’ (Mg5Si6) precipitates, whereas an unexpected Copper type texture develops upon rolling of AA 2195 alloy containing T1 (Al2CuLi) precipitates. The present work highlights that rolling texture evolution in the presence of shearable precipitates cannot be generalized and depends strongly upon the shearing propensity of these precipitates.

Effect of annealing on the microstructures and mechanical properties of Al/Mg/Al laminates

Al/Mg/Al laminates were fabricated by hot rolling at 400 °C and annealed at temperature ranging from 200 °C to 400 °C for 1 h to 4 h. Microstructural examination revealed that brittle intermetallics identified as Mg17Al12 and Al3Mg2 appeared at Mg/Al interface when annealing temperature exceeded 300 °C. Al layers in laminates annealed at 200 °C exhibited typical copper-type texture, which totally transformed to recrystallized cube texture at 400 °C with a higher intensity. Mg layers in annealed laminates presented (0002) basal texture with c-axis titling from normal direction (ND) to rolling direction (RD), and bimodal basal texture was observed at 400 °C. Recrystallization extent of Mg layer increased with the increase in annealing temperature and/or annealing time, and nuclei preferred to occur in grains near Mg/Al interface. Grain size, texture type of matrix, and thickness of intermetallic layers all influence mechanical properties of Al/Mg/Al laminates. Laminates annealed at 200 °C for 1–4 h exhibited better ultimate tensile strength (UTS) ranging from 223 MPa to 240 MPa and elongation (EL) ranging from 21% to 26%. Despite more extensive recrystallization of laminate annealed at 400 °C, thicker intermetallics greatly decreased its strength and plasticity because crack initials and quickly propagates along Mg/Al interface or in the interior of intermetallics.

Deformation Characteristics and Texture Development of Biadded Cu-29Zn Alloys

Theories regarding texture transition mechanisms of brass alloys and its critical deformation level of when the change of texture transition occurs are still in debate. Previous observation showed that copper type texture dominantly formed at high temperature process whereas brass type texture tended to occur at low temperature. In contrast, another research observed the occurrence of copper type texture at low strain level while higher strain level resulted in brass type texture. Thus further research is needed to affirm one that well-satisfy the actual texture transition phenomenon. In this research, Cu-Zn-xBi alloys were produced by gravity casting process using pure Cu and Zn ingots with varied Bi addition of 0.2, 0.4, and 0.8 wt. %. As-cast samples were homogenized at 800 °C for 2 h in a muffle furnace. The samples were then cold-rolled with the level of deformation of 20, 40, and 70 %. Characterization includes chemical composition analysis, microstructure observation, hardness testing, and texture measurement. Results showed that addition of Bi prompted Bi-rich dispersoid phase which segregated inside the grain and along the grain boundary in globular forms. Slip was dominant at 20 % deformation level and its density increased with the addition of Bi. At 40 % deformation, twinning replaced slip as the predominant mechanism. The twin density increased with higher Bi content. Further deformation at 70% produced shear bands and flattened the Bi dispersoid phase. Greater Bi content induced the formation of shear band. At 40% deformation, pole figure images show the trend of copper type texture with orientation of {112} <111> with intensity of 7.92. This texture was formed by mechanical twinning during deformation process. At 70 % deformation, samples illustrated the combination of brass and Goss type texture at orientation of {110} <112> and {110} <001> due to the shear band.

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.