Main Texture Components Research Articles

The variation of microstructures, textures and mechanical properties from edge to center in cross section of Ti6242s titanium alloy

Microstructures and textures determine the mechanical properties of metal materials. In this work, a Ti6242S bar with ϕ260*129 mm scale was selected to study variation of microstructures and textures from edge to center by Optical Microscope and X-Ray Diffraction. Owing to the less plane stress, fast cooling rate and complex flow stress, grains size are quietly fine and macrotextures are close to nearly random in edge, which lead to the most excellent and homogeneous mechanical properties. By comparing feature of microstructure in R/2 and center position, larger volume fraction of αs colonies formed in center. Meanwhile, the main texture components were (112¯0) [11¯00] and (112¯0)[0001] in R/2, but symmetrical cubic texture with very high intensity come into being in center. More and larger αs colonies combine high-density texture jointly cause tensile strength and yield strength drop dramatically in center. Young's modulus is mainly influenced by textures, due to different texture in different location, edge was the largest, following by the center and R/2. The spheroidization of αp laths was completed in edge by strain-induced but dynamic recrystallization in R/2 and center by analyzing grain boundary feature and misorientation of EBSD data.

The effect of Mn content on the texture of aluminium alloys in cold rolled and annealed state

The crystallographic texture greatly influences the properties of the cold rolled and hot rolled semi-products. As semi-products undergo further shaping (and heat treatment) before reaching their final condition, it is important to know their crystallographic texture. During our research, three different alloy aluminium alloys were tested (3003, 3103, unalloyed Al sheet) with different Mn content. In the first step the initial hot-rolled sheets were cold rolled to ∼1 mm thickness without intermediate annealing. In the second step the sheets were cold rolled to 3 mm and annealed. In parallel, an intermediate annealing was applied at ∼3 mm thickness for the 3103 alloy and subsequently cold rolled to 1 mm and annealed. The annealings were performed at 300°C for 3 hours in an air furnace. The resulting textures are characterized by the volume fractions of the main texture components, which were calculated from the orientation distribution function (ODF). The dominant texture components were determined for the different alloys in different states.

Characterization of crystallographic texture of Zirconium alloy components by neutron diffraction

The reproducibility of the determination of crystallographic texture of Zr-based components by neutron diffraction has been studied through a small round-robin exercise, with the participation of texture and residual stress diffractometers from five international laboratories. Both constant-wavelength and polychromatic neutron beams have been used to define the texture of specimens from a warm-rolled and annealed Zircaloy-4 plate, and from a Zr-2.5%Nb pressure tube. Measurements were also compared to synchrotron high energy X-ray diffraction experiments, as a complementary volumetric technique with much shorter data collection times compared to neutrons. Results are qualitatively consistent and reproducible in terms of pole figures and orientation distribution function, underlining the suitability of neutrons for bulk texture measurements. Expected uncertainty of measurements has been quantified by global parameters such as texture indexes and Kearns factors, and local parameters associated to the main texture components (volume fraction, centroids, and widths of fiber components). The typical uncertainties found for these parameters are compared to spatial differences found in a small batch of cold-rolled Zr-2.5%Nb pressure tubes.

Hot rolling of spark-plasma-sintered pure aluminium

ABSTRACTIn 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.

The influence of alumina nanoparticles on lattice defects, crystallographic texture and residual stresses in electrodeposited Ni/Al2O3 composite coatings

This paper presents how various additions of Al2O3 nanoparticles in the electrolytic bath modified the Ni/Al2O3 nanocomposite coating microstructure. The residual stresses, lattice defects, and crystallographic texture of the obtained deposits were studied. The investigations showed that the tensile residual stresses corresponded to the ceramic nanoparticles content in the deposited coating. The high level of measured stresses in the Ni/Al2O3 coatings indicated the presence of strengthening mechanisms caused by the Al2O3 nanoparticles. The density of crystal lattice defects and grain refinement contributed to the strengthening of the Ni matrix. The main texture components and lattice parameters were more sensitive to deposit thickness changes than to the amount of alumina nanoparticles embedded in the coatings. The Ni/Al2O3 with the smallest thickness showed the highest lattice parameters of the Ni matrix.

The nucleation of cube grains during primary recrystallization of aluminum

The formation of cube grains during recrystallization has been analyzed in commercial AA1050 alloy and pure Al single crystal of S{234}<524> orientation. Samples of AA1050 alloy were deformed along two deformation modes to form different as-deformed texture components and then lightly annealed. One group of the samples was plane strain compressed (PSC) in a channel-die. The second group was deformed by equal channel angular extrusion (ECAE). The results obtained on polycrystalline AA1050 alloy were compared with recrystallization behavior of PSC single crystal of S{234}<524> orientation. The textures were measured by SEM/EBSD and X-ray diffraction. It was found that a very weak residual cube{100}<011> component was observed in the samples of AA1050 alloy after both deformation modes. After annealing cube-oriented grains were extensively formed only in PSC samples. These grains were situated preferentially inside or in between the S-oriented areas with local disorientations about <111> axes. Cube-oriented grains were not formed during annealing of the ECAE samples, where main as-deformed texture components close to two complementary orientations of {124}<651>-type were transformed towards two components of ∼{100}<011> and ∼{221}<114>, essentially by <110> rotations. In single crystalline samples cube grains were extensively formed during annealing despite (near)cube-oriented areas haven’t been observed in the as-deformed microstructure.

Effect of niobium and phase transformation temperature on the microstructure and texture of a novel 0.40% C thermomechanically processed steel

Field emission scanning electron microscopy, electron backscatter diffraction (EBSD) and X-ray diffraction (XRD) have been employed to investigate the effect of niobium and phase transformation temperature on the evolution of microstructure and texture in a novel thermomechanically processed, medium‑carbon, low-alloy steel intended for slurry pipeline applications. Thermomechanical processing consisted of hot-rolling in the austenitic region with deformation both above the recrystallization limit temperature and below the recrystallization stop temperature. Immediately after rolling, specimens were directly quenched in water to two different temperatures of 560 °C and 420 °C and subsequently furnace cooled from those temperatures to simulate the cooling of coiled strip on a hot strip mill. The microstructure of samples quenched to 560 °C mostly comprised of upper bainite, whereas the samples quenched to 420 °C mainly consisted of lath-type lower bainite. The transformation texture of all samples at the mid-thickness position consisted of α, γ and ε-fibers with high intensities close to the transformed copper, transformed brass and rotated cube components. The addition of 0.013 wt% Nb refined the microstructure and sharpened the texture. The texture of the small fraction of retained austenite present in the final microstructures indicated that the main bcc texture components result from the brass and copper components in the parent austenite.

Effects of asymmetric feeder on microstructure and mechanical properties of high strength Al-Zn-Mg alloy by hot extrusion

The asymmetric feeder die extrusion was introduced on high strength Al-Zn-Mg alloy. The hot extrusion experiments were carried out using flat die without feeder, with symmetric and asymmetric feeders. The grain morphology, second particle distribution and microtexture were examined, and the tensile tests were performed along 0°, 45°, and 90° with extrusion direction. Moreover, the numerical simulation was performed to have a better understanding on the experimental findings. The results show that the utilization of feeder chamber results in the increase of effective strain and slight decrease of strain rate. The microstructure of all extruded plates consists of elongated grains and small amount of fine grains. The asymmetry feeder is favorable for the dynamic recovery process. Although the fraction of dynamic recrystallization is low in all cases, it is slightly higher in the plate extruded without feeder. The main texture components of the extruded plates are {110}〈111〉 Y, {001}〈100〉 Cube, and {110}〈112〉 Brass. The fraction of above mentioned texture varies significantly by the utilization of symmetric and asymmetric feeders. The elongation is greatly enhanced in the plates extruded by feeder die. Importantly, the anisotropy of elongation is obviously reduced in the plate extruded using the asymmetric feeder.

AZ31 마그네슘 합금의 어닐링 이후 내부마찰 거동

Specimens were machined out from hot-rolled AZ31 magnesium alloy, and deformed at 623K with rolling reduction of 30%. After hot rolling, specimens were annealed at various range of temperature and time. In this study, static recrystallization was occurred during heat treatment, however, variation of main component and intensity of texture was not revealed. The results of microstructure observation, damping capacity test and dislocation mechanism indicated that increasing of damping capacity was caused by grain growth. It means that grain size is effective factor to damping capacity.

Texture Inheritance on Phase Transition in Low-Carbon, Low-Alloy Pipe Steel after Thermomechanical Controlled Processing

Orientation microscopy (electron back scatter diffraction, EBSD) is used to investigate the structural and textural states of low-carbon, low-alloy pipe steel (resembling 06Г2MБ steel) after thermomechanical controlled processing (TMCP): heating to 1000°C with subsequent quenching in water; isothermal quenching with holding at 300°C; and slow cooling in the furnace. The heat treatment is associated with double phase recrystallization: α → γ → aht, where aht is martensite, bainite, or ferrite. The texture obtained after TMCP is mainly formed by two strong scattered orientations from {112}〈110〉and two weaker scattered orientations close to {110}〈223〉. Despite the double phase recrystallization, the main crystallographic orientations of the bainite after TMCP and after isothermal quenching are the same. That indicates structural and textural inheritance in the material. The structures obtained after other thermal treatments of the structure (both martensite and ferrite) also include complex multicomponent textures, which are nevertheless distinct. Some of the main textural components of martensite and ferrite are the same as bainitic components. All the structures after heat treatment have a similar spectrum of large-angle boundaries, with strongly expressed boundaries of the coincidence site lattices (CSL): Σ3, Σ11, Σ25b, Σ33c, and Σ41c. The orientations forming the texture of all the structures obtained are related to the main orientation of the deformed austenite grains formed on hot rolling in TMCP, in accordance with orientation relations intermediate between the Kurdjumov–Sachs and Nishiyama–Wasserman types. In all cases, the orientation relationship of the textural components of the initial material and the structure obtained by heat treatment may be explained in terms of the onset of phase transformations (both shear and diffusional transition) at crystallographically determined boundaries (including special boundaries) similar to the CSL boundaries Σ3 and Σ11.

Microstructural and texture evolution of Jethete M152 flanged-test pieces during cold rotary forging

Rotary forging is an attractive incremental metal forming with many advantages over any other processes, requiring smaller deformation force and providing high accuracy (near-net-process). The main applications of rotary forging process include families of bevel and helical gears, and flanged components for transmissions such as disk, rollers, wheels, etc. The main aim of this work is to study the impact of rotary forging process on the microstructural and texture evolution of high-strength materials, and martensitic stainless steels in particular, during cold rotary forging process. Jethete M152 alloy is a cold formable 13%-Cr martensitic stainless steel used in the aerospace industry. Jethete M152 flanged test-pieces were rotary forged at room temperature. The process was interrupted at 4 intermediate steps, providing flange reductions of 25, 30, 50, 65 and 70%. A complex grain flow and inhomogeneous deformation patterns are developed during rotary forging, characterized mainly by the formation of a strong deformation band which run parallel to the bottom die. A transition from asymmetrical bulging (inverted mushroom) to symmetrical bulging was observed as a result of the initial lower contact area of the preform with the bottom die. From microstructural analysis by EBSD, the lath structure of Jethete M152 is gradually reoriented and changes it shape in a direction parallel to the compression plane, developing a lamellar/pancake structure in those positions with maximum deformation. These microstructural changes are accompanied with the development of a strong texture formed by a duplex (100)+(111) fibers aligned with the compression axis, being the (111) fiber the stronger one. These findings are in good agreement with uniaxial compression for bcc metals. The analysis of the Orientation Distribution Figures (ODF) reveals that 4 main texture components are formed in the course of the rotary forging process: Brass {110}(112), L {110}(110), I {112}(110), and Cube {001}(100). In contrast with the reported literature for bcc metals, no texture component associated to the γ-fiber ({111} ‖ ND) was found.

EBSD investigation of Al/(Al13 Fe4 +Al2 O3 ) nanocomposites fabricated by mechanical milling and friction stir processing.

The application of ball-milling for reactant powders (Fe2 O3 +Al) to form in situ nanosized reaction products in the stir zone of 1050 aluminium alloy was examined and the evolution of microstructure, grain boundaries and microtexture of the fabricated Al/(Al13 Fe4 +Al2 O3 ) nanocomposite was investigated. The mean matrix grain size of the fabricated nanocomposites by the combination of ball milling and friction stir processing were found to be ∼3.2, 3.1 and 2.1 μm for 1, 2 and 3 h milled powder mixtures, respectively. The fraction of high-angle grain boundaries increased markedly in the stir zone indicating the occurrence of dynamic restoration of the aluminium matrix. This was also associated with increasing of the fraction of low ∑CSL boundaries. In addition, the fraction of high-angle grain boundaries increased as the reaction product increased. The developed textures were compared with the most important deformation and recrystallisation texture components of cubic close packed structure. Some of the main texture components formed due to the restoration of aluminium in the stir zone of the material with no powder addition were CubeND {001}<310>, BR {236}<385> and R (or retained S{123} <634>); these are usually found in the rolled materials. However, the presence of nanosized reaction products in the fabricated nanocomposite changed the texture components to the dominant Goss {011}<100>, P {011}<122> and R{124}<211> textures.

The Formation of Strong {100} Texture by Dynamic Strain-Induced Boundary Migration in Hot Compressed Ti-5Al-5Mo-5V-1Cr-1Fe Alloy

The microstructure and texture evolution of Ti-5Al-5Mo-5V-1Cr-Fe alloy during hot compression were investigated by the electron backscatter diffraction technique. The results reveal that two main texture components containing &lt;100&gt; and &lt;111&gt; fiber textures form after the hot compression. The fraction of each component is mainly controlled by deformation and strain rate. Dynamic strain-induced boundary migration (D-SIBM) is proved to be the reason that &lt;100&gt;-oriented grains grow towards &lt;111&gt;-oriented grains. The &lt;100&gt;-oriented grains coarsen with the increasing &lt;100&gt; texture intensity. Dynamic recrystallization (DRX) occurs under a low strain rate and large deformation. The DRX grains were detected by the method of grain orientation spread. The DRX grains reserve a &lt;100&gt; fiber texture similar to the deformation texture; however, DRX is not the main reason causing the formation of a strong &lt;100&gt; texture, due to its low volume fraction.

Influence of cerium on solidification, recrystallization and strengthening of Cu-Ag alloys

Cu-Ag-RE alloys with different Ce contents were prepared by vacuum melting, and microstructure evolution and mechanical properties of Cu-Ag-Ce alloys were investigated by optical microscopy, scanning electronic microscopy with electron back-scattered diffraction and tensile test. The results indicated that a columnar to equiaxed transition in cast Cu-Ag-RE alloys was observed due to Ce addition and area of the region with equiaxed grains enlarged with increasing Ce content. Cold-rolled Cu-Ag-RE alloys in annealed condition exhibited a partially or fully recrystallized grain structure depending on the concentration of Ce. The average grain size decreased and texture components changed with increasing Ce content. The main brass-type texture component changed to be copper-type as the Ce content increased from 0.05 wt.% to 1.0 wt.%. The Cu-Ag-RE alloy with 0.2 wt.% Ce showed maximum ultimate tensile strength, while the sample with 1.0 wt.% Ce showed a better comprehensive mechanical property.

Controlling grain structure and texture in Al-Mn from the competition between precipitation and recrystallization

The recrystallization behaviour of Al-Mn alloys (AA3xxx series alloys) is affected by randomly distributed dispersoids present before annealing, by dispersoids precipitated at grain/subgrain boundaries before the onset of recrystallization, and by dispersoids concurrently precipitated during recrystallization. In this study, the effects of these three populations of dispersoids on the recrystallization behaviour of a cold rolled AA3xxx alloy were analysed and compared using four temperature-time paths to different target temperatures. Changing the temperature-time path modifies the extent of recovery, the dispersoid structures, as well as the absolute recrystallization temperature, which then influences the final grain structure and recrystallization texture. In particular, an in-depth investigation on how different populations of dispersoids affect the main recrystallization texture components of AA3xxx alloys, i.e., P{011}〈566〉, ND-Cube {001}〈310〉, and Cube {001}〈100〉, has been carried out. The results clearly show that, as compared to isothermal annealing, annealing with more elaborate heating and annealing schedules (temperature-time paths) all lead to increased strength of the P texture component and decreased intensities of both the Cube and ND-rotated Cube texture components. The increase of P texture strength and average grain size is most significant when recrystallization occurs concurrently with precipitation. The controlling mechanisms behind this behaviour and the possibility to use them to tailor the grain structure and texture of similar alloys are further discussed.

Microstructure evolution during solution treatment of extruded Al-Zn-Mg profile containing a longitudinal weld seam

In this study, the microstructure evolution during solution treatment of extruded Al-Zn-Mg profile containing a longitudinal weld seam was firstly reported. The porthole die extrusion experiment was conducted to obtain the extruded profile. The solution treatment was performed at 470 °C for 15 min, 60 min and 120 min, respectively, and the aging was performed at 120 °C for 24 h. The secondary phase distribution, grain morphology, grain size and texture evolution of welding zone during solution were investigated. Moreover, the hardness and tensile properties after aging were analyzed. The results show that the solution for 15 min is sufficient for the dissolution of MgZn2 phase, while Al2CuMg and Al23CuFe4 phases cannot be dissolved even the solution time is prolonged to 120 min. The main texture components of {110}<111> and {110}<115> are formed after extrusion process, and these textures are remained after solution treatment. With increasing solution time, the intensity and volume fraction of texture firstly increases and then decreases. Furthermore, both the average size and aspect ratio of grains in welding zone increase with increasing solution time. The best hardness, tensile strength and elongation was obtained in the Al- Zn-Mg profile after solution treated for 15 min.

Formation process of the {001} fiber texture on iron particles using simple ball milling

The process of texture formation on iron particles was investigated via simple ball milling using graphite particles as milling aid. During milling, the shape of the iron particles changed from granular to platelets owing to repetitive compression and balls rolling in a direction perpendicular to the platelet faces. Simultaneously, a {001}+{111} double-fiber texture was formed, which is characteristic of a metal with a bcc structure deformed under uniaxial compression and multidirectional rolling. Based on these observations, it is concluded that the texture obtained through simple ball milling was induced by uniaxial compression and a multidirectional-rolling-like deformation. Since the main component of the double-fiber texture is {001} and the easy magnetization axes 〈001〉 are oriented toward the in-plane directions with the platelet face in the texture, the iron particles are ideal candidates for use as magnetic cores in motors, inductors, and other electromagnetic parts.

Evolution of high strength and ductile ultrafine grained dual phase superferrite low carbon V-Nb-Mo steel

The microstructural characteristics of dual phase steels mainly determined by the starting microstructure before inter-critical annealing. In the present research, for the first time, the ultrafine grained dual-phase low carbon V-Nb-Mo steel processed by using severe warm rolling and subsequent inter-critical annealing of the super ferrite starting structure. The microstructure, texture, and tensile behavior of the processed steel studied by electron backscatter diffraction, scanning and transmission electron microscopy, nanoindentation and tensile test. The results show that the superferrite offers abundant homogeneous nucleation sites. That led to significant grain refinement and homogenous dispersion of microstructure constituents. The microstructure of the processed steel was composed of equiaxed ultrafine ferrite grains with average size 0.95µm and ultrafine martensite blocks (̰ 0.65µm). Main texture components were α and γ-fibers. The steel revealed the yield strength of 945MPa, the tensile strength of 1400MPa, and total elongation of 23 pct. Also, fracture analysis exhibited a ductile failure mode. The appropriate combination of strength-elongation and ductile fracture of the steel are attributed to the high strain hardenability of ultrafine ferrite grains, the high plasticity of uniformly dispersed ultrafine martensite islands, and the presence of high density of nanosized carbides and dislocations in the microstructure.

Effect of copper precipitates on mechanical and magnetic properties of Cu-bearing non-oriented electrical steel processed by twin-roll strip casting

Microstructure, texture, precipitation, mechanical and magnetic properties in a twin-roll strip casting Cu-bearing non-oriented electrical steel were studied by a combination of X-ray diffraction (XRD), electron back-scattered diffraction (EBSD), optical microscopy (OM) and transmission electron microscopy (TEM). The results indicated that the average grain size and main texture component were not affected by aging time, while the size and crystal structure of copper precipitates were influenced. In the peak strength condition, copper precipitation contributed ~ 207MPa to the yield strength of the final product without deteriorating the magnetic properties. In summary, a non-oriented electrical steel with excellent mechanical and magnetic properties was successfully processed via twin-roll strip casting.

Preferred Orientation Contribution to the Anisotropic Normal State Resistivity in Superconducting Melt-Cast Processed Bi₂Sr₂CaCu₂O8+δ.

We describe how the contribution of crystallographic texture to the anisotropy of the resistivity of polycrystalline samples can be estimated by averaging over crystallographic orientations through a geometric mean approach. The calculation takes into account the orientation distribution refined from neutron diffraction data and literature values for the single crystal resistivity tensor. The example discussed here is a melt-cast processed Bi2Sr2CaCu2O8+δ (Bi-2212) polycrystalline tube in which the main texture component is a <010> fiber texture with relatively low texture strength. Experimentally-measured resistivities along the longitudinal, radial, and tangential directions of the Bi-2212 tube were compared to calculated values and found to be of the same order of magnitude. Calculations for this example and additional simulations for various texture strengths and single crystal resistivity anisotropies confirm that in the case of highly anisotropic phases such as Bi-2212, even low texture strengths have a significant effect on the anisotropy of the resistivity in polycrystalline samples.