Copper-type Texture Research Articles

Effect of Warm-Rolling on the Formation of Microstructure and Microtexture of the Constituent Phases in a Duplex Steel

The effect of warm-rolling on the evolution of microstructure and microtexture was investigated in a duplex steel. For this purpose annealed duplex steel plates were cold and warm-rolled up to 90% reduction in thickness at room temperature and at 625°C, respectively. The austenite volume fraction decreased consistently during cold-rolling indicating that austenite was not stable during cold-rolling. In contrast, austenite was found to be very stable during warm-rolling at 625°C. Development of an ultrafine lamellar deformation structure with alternate arrangement of the ferrite and austenite bands could be observed during warm-rolling. A strong pure metal or copper type texture was observed in the austenite in the warm-rolled material in contrast to brass texture developed during cold-rolling. Development of RD (RD//<110>) fiber and ND-fiber (ND//<111>) was observed in ferrite during both cold and warm-rolling. However, the strength of the RD-fiber was much higher as compared to the ND-fiber in ferrite in cold-rolled DSS as compared to the ferrite in warm-rolled DSS.

Effect of Warm Rolling on the Evolution of Microstructure, Microtexture and Mechanical Properties of Commercial Grade Duplex Steel

The effect of warm rolling on the evolution of microstructure, microtexture and mechanical properties of a duplex stainless steel (DSS) was investigated. For this purpose, the DSS alloy was warm rolled at 625°C up to 90% reduction of thickness. Development of ultrafine lamellar morphology with alternate arrangement of the two phases was revealed during warm rolling. The ferrite in DSS developed stronger RD-fiber (RD//<110>) than ND-fiber (ND//<111>) while austenite in DSS showed pure metal or copper type texture. The DSS in the as warm-rolled condition showed tremendous increase in ultimate tensile strength to∼1.4GPa. The present results demonstrate that warm rolling can be used successfully for developing ultrahigh strength DSS.

Evolution of Microstructure and Texture during Isothermal Annealing of a Heavily Warm-rolled Duplex Steel

The evolution of microstructure and texture during isothermal annealing of a heavily warm-rolled duplex steel (DSS) was studied. For this purpose a DSS steel was hot rolled, homogenized at 1448 K and subsequently warm-rolled to 90% reduction in thickness at 698 K and 898 K. This was followed by isothermal annealing at 1448 K for different time intervals up to 7200 seconds. Lamellar microstructure with alternate arrangement of deformed ferrite and austenite bands was observed in the as warm-rolled condition. The ferrite in DSS warm-rolled at 698 K showed much stronger α-fiber (Rolling direction (RD)//<110>) than γ-fiber (Normal direction (ND)//<111>) as compared to the ferrite in DSS warm-rolled at 898 K. The austenite in warm-rolled DSS showed a predominantly pure metal (or copper type) texture. Upon annealing the lamellar morphology of the as warm-rolled structure transformed into a bamboo type morphology for short annealing time but finally broke down with increasing isothermal annealing time due to mutual interpenetration of the two phases. Retention of deformation texture components and presence of annealing twins in austenite indicated discontinuous recrystallization. Despite differences of texture in the as warm-rolled condition the ferrite in annealed DSS showed much stronger α-fiber as compared to γ-fiber due to strong recovery behavior of ferrite during annealing. The texture evolution in the two phases was not affected by the presence of the other phase while grain growth was significantly restricted due to the presence of the other phase.

Effect of Change in Strain Path During Cold Rolling on the Evolution of Microstructure and Texture in Al and Al-2.5%Mg

The effect of change in strain path during cold rolling on the evolution of microstructure and texture is investigated. For this purpose, high purity aluminum and Al-2.5%Mg alloy are deformed (~90% reduction in thickness) by unidirectional and cross cold rolling. Irrespective of the alloy system, copper-type texture is observed in unidirectional processed materials, while strong brass ({011}〈112〉) texture is developed during cross rolling. Unidirectionally rolled aluminum showed higher HAGB fraction, but similar HAGB spacing as compared to the cross-rolled aluminum after 90% reduction in thickness. At the same time, the internal misorientation in the cross-rolled 2N-Al is higher than in the unidirectionally rolled material. In contrast, Al-2.5% Mg alloy processed differently in both ways shows similar HAGB fraction, spacing, and internal misorientation distribution. These observations indicate that microstructure evolution due to strain path change is more strongly affected by dynamic recovery as compared to texture evolution.

Texture Evolution of Columnar Grains in Electrical Steel During Hot Rolling

Columnar grains in cast slabs of electrical steel show strong anisotropy in grain orientation and morphology and thus influence the subsequent microstructure and texture after hot rolling significantly. The texture evolution of hot rolled sheets containing initial columnar grains with their <100> directions approximately parallel to the rolling direction (RD), transverse direction (TD) and normal direction (ND) of the hot rolled sheets was investigated by using EBSD technique. The results indicated that, whatever the initial texture of the columnar grains was, typical Goss, brass-type and copper-type shear texture component could develop in shear-deformed surface region. The copper-type texture formed under the maximum shearing force with the fine, sheared or dynamically recrystallized grains, and Goss grains were mainly elongated and deformed grains, while brass grains behaved between them. Additionally, the rotating relationship of the three types of shear textures was different due to the restriction of grain boundaries. In homogenously deformed center region, the RD sample contained more {112} <110> grains, and TD sample was covered by {100} textures such as {100}<011> and {100}<021> with coarse grains, while the ND sample developed many {100}<011> grains which were attributed to more {100} grains in the initial sample. Remarkable texture transition occurred on both sides of grain boundaries when {110} grains were adjacent to α-fiber texture grains. It was found that significant texture gradient and preferred distribution of rotating axis existed in the soft orientation grains on the α-fiber when the grains neighbored hard grains on γ-fiber.

Deformation behaviour at macro- and nano-length scales: The development of orientation gradients

The deformation behaviour of macrocrystalline and nanocrystalline nickel shows a striking similarity in terms of higher intragranular misorientation and a texture with dominant Brass component on rolling. This is in contrast to microcrystalline nickel, with lower intragranular misorientation and typical Copper type texture. This has been attributed to the free surfaces in macrocrystalline sample and grain boundaries in nanocrystalline sample. Experimental evidence of ‘Grain Boundary Affected Zone’ (GBAZ) showing multi-slip in contrast to limited slip in the grain interiors has been provided. The similarity in evolution of texture and intragranular misorientation is explained on the basis of reduced contribution from the GBAZ at the two extreme length scales.

The Brass-Type Texture – How close Are we to Understand it?

This paper summarizes a recent review about the brass-type texture and its deviation from the copper-type texture by the present author and R.K. Ray – with somewhat sharpened conclusions.

Experimental Investigation of Texture Gradients in Aluminium/Copper Plates Bonded through Explosive Welding Process

In this study, the commercial purity Al/Cu plates were bonded through the explosive welding process. The SEM/EBSD local orientation measurements were conducted to consider the changes in the microstructure and the development of texture gradients for the applied explosive loading. A particular attention was paid to the texture changes across the interface. The detailed local orientation measurements show that the ultra-fine grained layers are formed close to the bonding zone. The layers were characterized by the copper-type rolling texture components. The interface was outlined by a characteristic sharp transition between the two materials. However, in some places, local melted zones were also encountered, mainly in the front slope of the waves.

Texture and Microstructure of Invar&lt;sup&gt;®&lt;/sup&gt; Deformed by Asymmetrical Rolling

Asymmetrical rolling, in which the circumferential velocities of the working rolls are different, is a method to impose shear deformation in addition to the thickness reduction. As a consequence, the deformation texture can be modified as compared to the classical rolling. In this work, the asymmetrical rolling of invar (Fe-36%Ni) and the influence of the deformation route are studied. The Invar® alloy has been deformed by asymmetrical rolling with a 83% thickness reduction. The texture of the deformed alloy was measured by X-ray diffraction at different levels through the thickness: upper side- middle- down side. With asymmetrical rolling, the deformed texture is a copper type texture but the components were rotated about 5-7° around the Transverse Direction (TD) axis as compared to the ideal position of these components in the pole figure representation. The rotation of the pole figure is an indicator of the amount of shear really introduced in the material during asymmetrical rolling. Finally, a simple model was developed in order to establish the condition to obtain either shear texture or grain refinement.

Texture characteristics controlled by single slip plane slipping in the warm-rolled Fe-14Mn-5Si-9Cr-5Ni shape memory alloy

To clarify the texture evolution mechanism of Fe-Mn-Si-based shape memory alloys, the rolling texture of an Fe-14Mn-5Si-9Cr-5Ni shape memory alloy is investigated during rolling to a final reduction of 82% at 873 K. A new rolling texture caused by single slip plane slipping is observed from such alloy, which is different from the conventional copper-type and brass-type textures. By means of the {111} pole figure scattering analysis of the local deformation structure, we conclude that such single slip plane slipping results in the weakness of brass orientation in the α fiber and the great enhancement of β fiber connecting S′ {331}&lt;213&gt; and B′ orientations {110}&lt;114&gt;.

A comparison of viscoplastic intermediate approaches for deformation texture evolution in face-centered cubic polycrystals

We present a comparison between two intermediate viscoplastic approaches: the self-consistent approach and the ϕ-model for the texture development in face-centered cubic polycrystals. In these models, the interactions between a grain and its surroundings are taken into account in different ways. We performed different tests to simulate axisymmetric tension/compression and plane-strain compression for different values of the parameter ϕ and for different formulations of the self-consistent model. Predicted results (stress–strain, texture, slip activity, local stress and strain rate deviations) are compared and conclusions are drawn. The ϕ-model allows for fairly good predictions, in comparison to existing experimental results, while it is much easier to formulate and to implement numerically. The ϕ-model is also able to predict texture transition from the copper type to the brass type. Using the same boundary conditions and spherical grains, the self-consistent model is unable to predict this texture transition and only a copper type texture is obtained.

Texture evolution analysis of warm-rolled Fe–28Mn–6Si–5Cr shape memory alloy

Since texture control tends to be a promising way to improve the shape memory effect (SME) of polycrystalline Fe–Mn–Si shape memory alloys, rolling texture evolution of an Fe–28Mn–6Si–5Cr shape memory alloy was systematically investigated with orientation distribution functions (ODFs) and electron backscattering diffraction (EBSD) analysis. At the rolling temperature of 873K, Copper-type texture components, including D, S, Goss, as well as a weak Brass, obviously develop before 44% rolling reduction. With increased rolling reduction to 57%, D orientation abruptly disappears, which indicates a texture transition has occurred. S orientation and α fiber texture except the Goss orientation undergo a decrease accompanying the intensification of γ fiber texture. In the whole deformation processes, Goss orientation is the dominant texture component while no pronounced Brass component is observed. The dominant Goss component can be attributed to the preferred Goss orientation both in shear bands and in matrix. When the rolling temperature is decreased to 573K, even at the early deformation stage, 42% rolling reduction, both D and Brass orientations are not observed. EBSD analysis confirms that the texture evolution is promoted to the early deformation stages at lower rolling temperature.

Texture Evolution in Invar&lt;sup&gt;®&lt;/sup&gt; Deformed by Asymmetrical Rolling

Asymmetrical rolling, in which the circumferential velocities of the working rolls are different, is a method to impose shear deformation and in turn shear deformation texture to sheet through the thickness. The Invar® alloy has been deformed by asymmetrical rolling with a 84% thickness reduction. The texture of the deformed and annealed alloy was measured by X-ray diffraction at different levels through the thickness: upper side- middle- down side, with unidirectional rolling. The deformed texture is a copper type texture but the components were rotated about 5-7° around the Transverse Direction (TD) axis as compared to the ideal position of these components in the pole figure representation. During recrystallization, the rolling components (brass {011}&lt;112&gt;,copper {112}&lt;111&gt;, aluminum {123}&lt;634&gt;) decrease quickly whereas the cube component {001}&lt;100&gt; is preferentially developed after a short annealing time. However, the rolling components do not disappear completely after complete recrystallization (120 minutes annealing). As a consequence the final texture contains a high cube component and rolling components.

Deformation-induced phase transformation and strain hardening in type 304 austenitic stainless steel

Deformation-induced phase transformation in a type 304 austenitic stainless steel has been studied in tension at room temperature and −50 °C. The evolution of transformation products was monitored using X-ray diffraction (XRD) line profile analysis of diffraction peaks from a single XRD scan employing the direct comparison method. Crystallographic texture transitions due to deformation strain have been evaluated using (111) γ pole figures. The tensile stress-strain data have been analyzed to explain the influence of underlying deformation-induced microstructural changes and associated texture changes in the steel. It is found that the initial stage of rapidly decreasing strain hardening rate in type 304 steel is primarily influenced by hcp ɛ-martensite formation, and the second stage of increasing strain hardening rate is associated with an increase in the α′-martensite formation. The formation of ɛ-martensite is associated with a gradual strengthening of the copper-type texture components up to 15 pct strain and decreasing with further strain at −50 °C. Texture changes during low-temperature deformation not only change the mechanism of ɛ-martensite formation but also influence the strain rate sensitivity of the present steel.

An Intermediate Viscoplastic Model for Deformation Texture Evolution in Polycrystals

The aim of this work is to discuss a new non linear intermediate model for large viscoplastic deformations that could predict the texture transition and stress-strain behavior in a range that spans from the upper bound (Taylor) to the lower bound (Sachs or static) estimates. In this model, we introduced a single parameter, f , as a weight function to formulate the proposed intermediate approach which combines the Taylor and Sachs estimates. This formulation leads to an interaction law by the minimization of a tensorial function which depends on the parameter f . For the applications, we focus on the uniaxial tension test. The results for texture evolution in an FCC polycrystal show that a transition between the copper type and brass type textures can be obtained by the proposed non-linear intermediate model.

Texture Transition in Ag-Pd Alloy Substrate for Superconducting Tapes

In order to demonstrate the effect of deformation temperature on texture formation in silver alloy sheet for superconducting types, the deformation and annealing textures of Ag-10 at% Pd alloy rolled at the temperatures from -1960C to 1600C and subsequently annealed were examined. A single Copper type texture with high intensity in ODFs has been realized in this study. Based on the experimental results, a metallurgical processing to get a sharp single orientation type texture in Ag-Pd alloy has been presented for manufacturing highly oriented superconducting substrate tapes.

Rolling and Recrystallization Textures of Ag-10 mol% Pd Alloy Substrate for Superconducting Tapes

In order to demonstrate the effect of deformation temperature on texture formation in silver alloy sheet for superconducting tapes, the rolling and annealing textures of Ag-10 mol% Pd alloy rolled at the temperatures from-196 to 160°C and subsequently annealed were examined in detail. The roll ing texture for all deformed specimens rolled at temperatures from -196 to 160°C consisted of a certain component near the Brass {110} (112) orientation with some weak components. During annealing procedure, the characteristic components of deformation texture disappeared quickly in specimens rolled at room temperature or -196°C but slowly in those warm-rolled at 120°C or 160°C. The Copper component was found to be formed by higher temperature annealing in specimens warm-rolled at 160°C and those rolled at room temperature. Above all, a single {112} (111) Copper type texture with high intensity in ODFs has been realized in three different specimens, which were rolled by 92% at room temperature or warm-rolled by 92% or 95% at 160°C and subsequently annealed as 200°C-10 min + 500°C-30 min + 800°C-180 min + 950°C-180 min respectively. From the experimental results obtained here, a metallurgical processing to get a sharp single orientation type texture in Ag-10mol% Pd alloy was presented for the development of new technology on oriented superconducting substrate tapes.

Microstructure and Texture Analysis in Twin-Roll Strip Cast Fe-36wt%Ni Alloy

Fe-36wt%Ni alloy sheet was produced using a vertical type twin roll strip casting process followed by cold rolling and annealing. The microstructure and texture through the thickness direction of as-cast strip, in cold rolled and annealed specimens were studied using Orientation Distribution Function (ODF) calculated from X-ray diffraction, optical microscopy and OIM (Orientation Imaging Microscopy). The columnar dendrites zone had been tilted by an angle of 25° to 30° from the strip normal direction. In the dendrites zone, {100} fiber texture evolved through the thickness direction. In the center layer, minor copper type texture component was formed. During the strip casting, plane strain compression in the center layer could be the reason for the evolution of the copper component. During cold rolling, s-fiber texture which is a typical deformation texture in FCC metals was developed but weak cube component was evolved simultaneously. Strong {100} , cube texture, was most likely formed during the final annealing of the cold rolled strip.

Texture evolution during cold rolling and recrystallization of L1 2-type ordered Ni 3(Si,Ti) alloy

Texture evolution during cold rolling and recrystallization of L1 2-type ordered Ni 3(Si,Ti) (Ni 79Si 11Ti 10, denoted by at.%) alloy was investigated. The starting material with no preferential orientation was cold rolled up to 80% reduction, and then fully recrystallized by annealing at 1173 K for 1 h. After cold rolling, a copper type texture composed of the α- and β-fiber textures with the strongest component of {011}〈211〉 orientation was developed. The recrystallization textures depended on rolling reduction. For the 30% reduction, no textural change was observed, while above 50% reduction the recrystallization textures were quite weak, but {011}〈100〉 and {001}〈110〉 orientations apparently existed. Based on these results, formation mechanism for cold rolling and recrystallization textures of the Ni 3(Si,Ti) alloy was discussed and compared with those of other L1 2-type ordered alloys.

“in-situ” neutron diffraction study of the cube crystallographic texture development in Fe53%-Ni alloy during recrystallization

Laboratoire de physico-chimie de l’e´tat solide, U.M.R. 8648, Baˆt. 410, 91405 Orsay, France(Received February 24, 2000)(Accepted in revised form April 3, 2000)Keywords: Texture; Recrystallization and recovery; Iron-nickel alloyIntroductionMany investigations have been carried out on the recrystallization crystallographic texture of rolledmetallic materials. However, the formation mechanism of the recrystallized grains with a preferredorientation has not been clarified yet. In particular, in the case of fcc metals and alloys from mediumto high stacking fault energy such as FeNi alloys, the cube texture {100},001. development duringrecrystallization is not clearly understood in spite of intensive studies. Several mechanisms have beenproposed to explain this phenomenon and two main alternative theories are generally proposed: orientednucleation (1) and oriented growth (2). Nevertheless, these theories are not satisfactory to explain fullythe cube texture development during recrystallization and in particular, they can not give any infor-mation on the time scale of the phenomenon. In this purpose, “in situ” texture measurements duringrecrystallization have been performed.The Fe53%-Ni alloy is widely used as soft magnetic sheet materials. After high reduction, cold rolledtexture is characterized by three main components considered as a typical copper-type texture (3): the“brass” {110} ,112. (B), the “aluminium” {123} ,634. (S) and the “copper” {112} ,111. (C)components. After annealing, a typical strong cube texture {100},001. development is observed.The aim of this paper is to study the crystallographic texture evolution of the Fe-53%Ni alloy duringannealing and the influence of the annealing temperature on the recrystallization kinetics. Then, the useof neutron diffraction is particularly requisite on the one hand to achieve good statistic measurement,even for small texture volume fraction and, on the other hand to use complex sample surroundings, asa furnace, necessary for the “in-situ” recrystallization study.Experimental ProcedureAfter hot rolling, the Fe-53%Ni alloy was cold rolled with a 95% reduction, until a final thickness sheetof about 0.2 mm. So in order to perform “in-situ” texture measurements by neutron diffraction, a pileup of 50 pieces (1cm 3 1cm) is realized in a vanadium (almost “transparent” for neutron diffraction)cubic container (1cm