X-ray diffraction study of the structural evolution in a grade 1469 (Al-Cu-Li) alloy during the production of hot-rolled sheets

X-ray diffraction is used to study the structural changes in a grade 1469 (Al-Cu-Li) alloy with a high lithium content that occur during the production of hot-rolled sheets according to the ingot → pressed strip → hot-rolled sheet schedule. In the pressed strip, a multicomponent Bs {110}〈112〉, Cu {211}〈111〉, and S {123}〈111〉 texture forms, which is typical of articles pressed from such alloys, and an unusual intense single-component texture of the Ex₁ {011}〈111〉 type forms in the hot-rolled sheets. Its formation is stimulated by cross rolling of the sheets. The low strength characteristics of the hot-rolled sheets after heat treatment are related to an elevated heating temperature used for quenching and to the oriented precipitation of the lamellar particles of the hardening T ₁ phase.     

Influence of initial ingot breakdown on the microstructural and textural development of high-purity tantalum

The influence of initial ingot breakdown on the rolling and recrystallization textures of high-purity tantalum plate was investigated using optical microscopy and X-ray diffraction. The four ingot breakdown processes investigated include two commercial processes and two processes new to tantalum. Correlations among the four ingot breakdown processes, the recrystallized grain size, and the final texture were established. Of the four breakdown processes investigated, the plate from the completely upset-forged ingot had the strongest {111}<110> and {111}<112> texture components, while the plate from the side-forged ingot recrystallized with a mixed texture. Increased upset forging along the ingot centerline strenghened the {111}<uvw> orientations and weakened the {100}<uvw> orientations in the annealed plates. Recrystallization studies were conducted on the rolled plates to develop an optimum texture with both {111}<110> and {111}<112> texture components in the final recrystallized plate.     

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.     

Precipitation Behavior and Textural Evolution of Cold-Rolled High Strength Deep Drawing Dual-Phase Steels

Low-carbon Cr-Mo micro-alloyed deep drawing dual-phase steels were designed in laboratory. As the microstructure and texture evolution in hot-rolled strips and annealed sheets were investigated using SEM, TEM and XRD technologies, the attribution of solute Mo and MoC particles to DP sheets' drawing capacity was investigated. The precipitation thermodynamics were also calculated by Thermo-calc software. Results show that the precipitates in hot-rolled strips mainly are MoC, AlN and MnS, and with the increase of Mo-addition, finer and denser MoC particles precipitated in matrix and along grain boundaries of ferrite more easily. Weak textures are shown in the hot-rolled strips, and {112}<110> and {223}<110> components tend to be stable in subsequent cold rolling process. During annealing, on one hand, the development of <111> // ND texture is suppressed because finer MoC particles prevent the grain boundary migration. On the other hand, unfavorable texture {001}<110> significantly reduces with Mo increasing, which is attributed to that part of solution C in matrix has been fixed during recrystallization. In addition, the addition of Mo can enhance hardenability strongly and MoC easily re-dissolve at high temperature, which is favor to form martensite in dual-phase steel.     

Deformation textures of AA8011 aluminum alloy sheets severely deformed by accumulative roll bonding

A fully annealed AA8011 aluminum alloy sheet containing a number of large particles (∼5 μm) was severely deformed up to an equivalent strain of 12 by an accumulative roll-bonding (ARB) process. The texture evolution during the ARB process was clarified, along with the microstructure. The ARB-processed aluminum alloy sheets had a different texture distribution through the sheet thickness, due to the high friction between the roll and the material during the ARB process. The shear textures composed of {001} 〈110〉 and {111} 〈110〉 orientations developed at the sheet surface, while the rolling textures, including Cu {112} 〈111〉 and Dillamore {4,4,11} 〈11,11,8〉 orientations, developed at the sheet center. The textural change from a shear texture to a rolling texture at the sheet center during the ARB process contributed to an increase in the fraction of high-angle boundaries. Also, a large number of second-phase particles in the AA8011 alloy sheets weakened the texture. Up to the medium strain range (below ɛ=6.4), relatively weak textures developed, due to the inhomogeneous deformation around the second-phase particles; after the strain of 6.4, strong rolling-texture components, such as the Dillamore and Cu orientations, developed. This remarkable textural change can be explained by the reprecipitation of fine particles in grain interiors.     

Evolution of Through-Thickness Texture in Ultra Purified 17%Cr Ferritic Stainless Steels

 Texture inhomogeneity usually takes place in ferritic stainless steels due to the lack of phase transformation and recrystallization during hot strip rolling, which can deteriorate the formability of final sheets. In order to work out the way of weakening texture inhomogeneity, conventional hot rolling and warm rolling processes have been carried out with an ultra purified ferritic stainless steel. The results showed that the evolution of through-thickness texture is closely dependent on rolling process, especially for the texture in the center layer. For both conventional and warm rolling processes, shear texture components were formed in the surface layers after hot rolling and annealing; sharp α-fiber and weak γ-fiber with the major component at {111}<110> were developed in both cold rolled sheet surfaces, leading to the formation of inhomogeneous γ-fiber dominated by {111}<112> after recrystallization annealing. In the center layer of conventional rolled and annealed bands, strong α-fiber and weak γ-fiber textures were formed; the cold rolled textures were comprised of sharp α-fiber and weak γ-fiber with the major component at {111}<110>, and inhomogeneous γ-fiber dominated by {111}<112> was formed after recrystallization annealing. By contrast, in the centre layer of warm rolled bands, the texture was comprised of weak α-fiber and sharp γ-fiber, and γ-fiber became the only component after annealing. The cold rolled texture displayed a sharp γ-fiber with the major component at {111}<112> and the intensity of γ-fiber close to that of α-fiber, resulting in the formation of a nearly homogeneous γ-fiber recrystallization texture in the center layer of the final sheet.     

Effects of Rolling Parameters on Texture and Formability of High Strength Ultra-Low Carbon BH Steel

 The effects of hot rolling and cold rolling parameters on texture and r (plastic strain ratio) value of high strength ultra low carbon bake hardening (ULC-BH) steels are studied with orientation distribution function (ODF) structural analysis method. After hot rolling, the high strength ULC-BH steel sheet has weak γ-fiber with uniform orientation distributions, and weak α-fiber, of which {445}<110> component forms a high intensity peak at coiling temperature of 750 ℃. After cold rolling, both {111}<110>-{111}<112> intensity on the γ-fiber and {111}-{112}<110> intensity on the α-fiber enhanced. As a result of substitutional solute elements Mn and P being added to the steel, strong {112}<110> deformation texture component is observed on α-fiber, especially at 80% cold rolling reduction, and this leads to the strong {111}<112> recrystallization texture after annealing. The increase of cold rolling reduction shifts the maximum intensity on the γ-fiber from {111}<112> to {111}<113>. After annealing, a very strong γ-fiber is obtained, with intensity peak at {111}<112> component when cold rolling reduction reaches 80%. Increasing coiling temperature and cold rolling reduction improve γ-fiber intensity and r value, resulting in good deep drawability.     

Formation of textures in a C–Si–V dual-phase steel

A vanadium microalloyed steel (0.1 C, 1.50 Si, 0.1 V) was subjected to initial heat treatments and intercritical annealing at 750 and 810°C to produce dual-phase structures of different distribution. Intercritically annealed materials were cold-rolled to a reduction of 60% in thickness and small samples taken from them were recrystallisation annealed at two temperatures of 650 and 800°C for various lengths of time. The (110) pole-figures for the cold-rolled materials with different dual-phase distribution showed a strong {111}< 112 > and a rather weak {111}< 110 > texture components. The O.D.F. (orientation distribution function) plots also showed the major texture components, {111}< 112 > and {111}< 110 > along with the minor components, like, {337}< 110 >, {337}< 776 >, {112}< 111 > and {112}< 110 >. No complete {111} fibre has been observed in the present investigation. Further the orientations{11, 11,4}< uvw > and {337}< uvw > have been found to be present as weak and incomplete fibre. The (110) pole-figures of the recrystallised materials have shown similar features (with reduced pole densities) as compared to the cold-deformed materials. Similarly, no {111} fibre has been observed in the recrystallised materials. The behaviour of the other two components, namely {11, 11,4}< uvw >, and {337}< uvw > have been found to be similar to that in the cold deformed material.     

Effect of intermediate heat treatment on microstructure and texture evolution of continuous cast Al-Mn-Mg alloy sheet

The microstructure and crystallographic texture evolution of continuous-cast, hot-rolled Al-Mn-Mg alloy sheet during cold rolling and subsequent annealing was investigated. All specimens cut from the as-received sheet were cold rolled and subsequently annealed, with some of these specimens receiving an intermediate heat treatment (IHT) prior to cold rolling. It was found that the degree of deformation and temperature of the annealing had a significant effect on the final grain size and texture of the sheet specimens, respectively. Furthermore, the IHT altered the development of the microstructure and texture of the final sheet specimens when compared to similarly produced specimens without it. For the sheet specimens without the IHT, a severely elongated grain structure was found in which the texture was dominated by a strong P orientation {011}<566>, despite the fact that the specimen was completely recrystallized. In contrast, specimens receiving the same cold rolling and annealing conditions but with the IHT had an equiaxed grain structure with a sharp Cube orientation {001}<100>. Counterbalancing the deformation textures from rolling with a sharp Cube orientation from annealing may lead to reduced earing behavior of CC Al-Mn-Mg alloy sheet products during deep drawing applications.     

Microstructural Evolution and Crystallographic Texture Formation of Cold Rolled Austenitic Fe‐30Mn‐3Al‐3Si TWIP‐Steel

The microstructural and texture evolution of cold rolled low stacking fault energy fcc Fe‐30Mn‐3Al‐3Si alloy was investigated as a function of the cold rolling strain. The alloy was melted and cast in a vacuum induction furnace, hot rolled and annealed before being cold rolled at three different strains: ε = 0.035, e = 0.2 and ε = 1.2. During the cold rolling process different deformation mechanisms became active depending on the strain. At low strain levels, ε = 0.035 and ε = 0.2, slip traces were observed whereas at higher strains shear bands appeared. The brass orientation {110}<112> spreading towards the Goss orientation {110}<001> was dominant at every strain level. The intensity of these texture components increased with increasing rolling strain. The increase of the brass component was more pronounced when e varied from 0.035 to 0.2, whereas the increase of the Goss component was more pronounced when ε varied from 0.2 to 1.2. Additional texture components developed: the E orientation {111}<110> lying on the γ‐fibre and the S orientation {123}<634> lying on the ß‐fibre. This evolution is comparable to other low SFE fcc materials exhibiting the brass‐type texture.     

Influence of hot-rolling conditions on texture development in deep-drawing steels

As the textures of deep-drawing sheet steels are important for certain material properties the purpose of this paper was to take a closer look at the hot-rolling, cold-rolling and annealing textures of different deep-drawing steel grades. Several Al-killed mild steels and vacuum-degassed Ti-IF steels have been hot rolled in the mill varying the finishing temperature (FT). After coiling, cold rolling and short-time annealing the textures at different thickness levels have been measured by means of (110)-pole figures and orientation distribution functions (ODFs). For both steel groups the textures at the surface of the hot strip exhibit a more or less pronounced shear type character. Towards the mid-thickness level (with lower FT more clearly) typical (cold-) rolling textures exist characterized by a strong {001}<110> orientation and in the Ti-IF steels additionally by a significant {112}<110> orientation density. In the case of high FT cold rolling and annealing lead to favourable {111}-textures where deep-drawing application is concerned. For the Al-killed steels lowering FT results in diffuse recrystallization textures whereas in the Ti-IF steels a sharp texture with near {223}<582> orientations can be observed which have not been known for these steels before. The results prove that the hot strip textures can be of great importance for the resulting annealing textures and the according material properties.     

The growth of single crystal Terfenol-D crystals

Rods of the highly magnetostrictive material, Terfenol-D, Tb_0.3Dy_0.7Fe₂, have been prepared by both Bridgman and float zone techniques. It is found that the dendritic growth front consists of parallel sheets of dendrites growing with a primary direction of <112> and sheet planes of {111}. Unseeded rods show a strong preference for <112> alignment of the grains. Seeding experiments have been successful for <112> orientations but not <111>, and the cause of this difference is discussed. The <112> single crystal rods are seen to contain parallel {111} twin boundaries throughout their volume, growing near the central plane of the dendrite sheets. These results are analogous to those of Ge and Si. The role of the twin planes on domain wall motion and methods of eliminating the twins are discussed.     

Formation of Nuclei With {111}<110> and {111}<112> Orientations of IF Steel at Early Stage of Recrystallization Using EBSD Analysis

The excellent deep drawability of interstitial free steel (IF steel) is closely related to its texture formed during recrystallization. The nucleation process of cold rolled IF steel at the early stage of recrystallization was investigated by electron back scattered diffraction (EBSD). The characteristics of the microstructure after deformation and the orientation of nucleation were observed. The results show that the deformed microstructure with 80% reduction could be subdivided into two groups. These two types of microstructure were characterized by their orientation and internal local misorientations. The nuclei with γ-orientation preferred to form in deformed bands with γ-orientation and at the boundaries between deformed grains with different orientations. The recrystallized grains with {111}<110> orientation appeared firstly in deformed matrix with {111}<112> orientation and consumed the matrix with {111}<112> to grow up, while the recrystallized grains with {111}<112> orientation were observed secondly in deformed matrix with {111}<110> orientation and consumed matrix with {111}<110> to grow up.     

Texture Development in the Ni47Ti44Nb9 Shape Memory Alloy During Successive Thermomechanical Processing and Its Effect on Shape Memory and Mechanical Properties

For improving the shape memory performance and mechanical properties of shape memory alloys (SMAs), crystallographic texture and second phase are generally induced in SMAs by suitable thermomechanical processing. For this purpose, the development of texture in the Ni₄₇Ti₄₄Nb₉ SMA during successive processing (e.g., hot forging, hot rolling, cold rolling, and heat treatment) and the effects of texture, grain size, and β-Nb particle precipitation on recoverable strains and tensile properties were studied. In the hot-forged and hot-rolled Ni₄₇Ti₄₄Nb₉ alloy rods, intense 〈111〉 fibers are formed, and water quenching from 873 K and 1123 K (600 °C and 850 °C) leads to the decrease in intensity of 〈111〉 fiber in the hot-rolled rod. When the hot-forged rod is hot-rolled into sheet, intense {001} and weak {123} fibers appear, but grain growth leads to the disappearance of {001} fiber and {110}〈001〉 becomes the strongest component. Cold-rolling deformation of the hot-rolled sheet promotes the development of γ-fiber and the convergence of {332} and {123} fibers to {233}〈110〉 and {123}〈121〉 components, respectively, and the intense component is turned into {111}〈110〉; in this case, the recoverable strain (ε _SRS) and tensile yield strength (σ _YS ) exhibit an anisotropy. When the quenching temperature is 1123 K (850 °C), some weaker components appear, the anisotropy of ε _SRS disappears, and the difference level in σ _YS along the rolling direction (RD) and transverse direction (TD) becomes smaller. Therefore, an appropriate heat-treatment temperature should be selected to maintain the deformation texture and also to obtain fine grains for different thermomechanical processing.     

Hot rolling of spark-plasma-sintered pure aluminium

In the present study, aluminium sheets were produced through the hot rolling of Spark-Plasma-Sintered (SPSed) discs. The effects of post possessing on the microstructure, texture and mechanical properties of the SPSed and hot-rolled specimens were studied using SEM-EBSD, tensile and microhardness tests. It has been shown that the hot-rolled specimens depict finer and equiaxed microstructure if compared with the SPSed ones. In addition, tensile properties improved in the hot-rolled specimens if compared with those belonging to the SPSed materials. This behaviour was attributed to porosity reduction, dynamic recrystallisation phenomena, grain refinement and formation of new grain boundaries. Although S {123} <634> was the main texture component in SPSed sample. Cube component {011} <211> formed after hot rolling.     

Crystallite orientation distribution analysis of the cold rolled and recrystallization textures in low-carbon steels

The development of the cold rolled and recrystallization textures in low-carbon rimmed and killed steels was investigated using the crystallite orientation distribution analyses. With increasing cold reduction low-carbon steels exhibit the simultaneous development of a partial <110> fiber axis parallel to the rolling direction and a <111> fiber axis parallel to the normal direction. The strongest individual texture component rotates from a {111} <110> at 60 pct cold reduction towards a {112} <110> at 80 pct. During the early stages of recrystallization the (110) and <111> fiber textures decrease in both the rimmed and killed steels. However, the decrease in the <111> fiber texture is greater in the rimmed than in the killed steel. With further recrystallization and grain growth this <111> fiber texture increases in both steels but to a greater extent in the killed steel. The strongest individual texture component after complete recrystallization is the {111} <110>, being ∼5.5 and ∼3.0 times random in the killed and rimmed steel, respectively.     

退火工艺对3.15 % Si冷轧无取向硅钢组织和织构的影响

试验研究了退火温度（850~950℃）和时间（5~18 min）对2.3 mm热轧硅钢板（/%:0.036C,3.15Si,0.21Mn,0.005P,0.007S,0.032Al）6道次轧制的0.35 mm冷轧板组织和织构的影响。结果表明,退火温度越高,晶粒平均尺寸越大,900℃5 min退火时平均晶粒尺寸41.39μm,试样织构主要集中在γ取向线上的{111}＜112＞;织构组分和{111}＜110＞;织构组分;900℃18 min退火时平均晶粒尺寸为48.08μm,试样的{111}面织构和{112}面织构密度都明显减弱,{001}面织构增强,磁性能较优。     

Competition among {110}, {112}, and {123} <111> slip modes in BCC metals

The conditions for the activation of various combinations of {ll0} <111>, {112} <1ll>, and {123} <111> slip modes have been examined by analyzing the yield loci. It is found that {ll0} slip will occur in preference to the other two modes if α > 1.155 and α₂ > 1.134, where α₁ and α₂ are respectively the critical resolved shear stress for slip on {112} and {123} systems relative to {ll0} slip. Slip occurs on {112} systems alone if α₁ < 0.866 and α₁ < 0.917α₂: and on {123} systems alone if α₂ < 0.945 and α₂ < 0.982α₁. The influence of {112} slip asymmetry and {112} <111> twinning on the choice of deformation modes has also been analyzed.     

Textures and Properties of Hot Rolled High Strength Ti-IF Steels

The texture evolution in a high strength Ti-IF steel during the processing of hot rolling, cold rolling, and annealing is studied. For comparison, both ferrite rolling and austenite rolling are employed. It is found that the texture type is the. same after ferrite rolling and austenite rolling, but the texture intensity is much higher in the ferrite rolled sample. Furthermore, texture characteristics at the surface are absolutely different from those at the mid sec tion in both ferrite rolled and austenite rolled samples, as well as under the cold rolled and annealed conditions. The shear texture { 110 } 〈001 〉 disappears and orientation rotates along { 110 } 〈001 〉→ { 554 } 〈 225 〉→ { 111 } 〈 112 〉→{111}〈110〉→{223}〈110〉 during cold rolling. Compared to the austenite rolled sample, the properties of the cold rolled and annealed sheet which is subjected to ferrite rolling are higher.