Fiber Texture Research Articles

Effect of texture on bending behavior of Mg alloy sheets

The effect of Li elements on the microstructure and texture evolution of AZ31 alloy sheets during room-temperature three-point bending was investigated. The results showed that the conventional c-axis//ND basal texture of the extruded AZ31 sheet could be modified to a TD-elongated fiber texture with a 5 wt% Li addition. As a result, the room-temperature bendability of the Mg–3Al–5Li sheet was improved effectively, and this sheet showed a minimum bending radius of only 2 mm. The superior bendability exhibited surpasses the room-temperature bending capabilities commonly observed in the majority of commercial Mg alloys. The improvement in bendability of the Mg–3Al–5Li sheet was attributed to the TD-elongated texture distribution. This type of texture distribution may offer more effective deformation modes to alleviate thickness strain during bending in comparison to the texture in extruded AZ31 sheets. This study could provide insights into developing Mg alloys with high room-temperature bendability by tailoring texture distribution rather than texture weakening.

Deformation mechanism and properties evolution of a copper alloy with ultra-high strength after cold drawing and subsequent aging treatment

In this study, the microstructure and properties evolution of Cu-2.7Ti-0.2Fe alloy (wt.%) during cold drawing and subsequent aging treatment were investigated. The grain refinement mechanisms of the samples were analyzed in detail and systematically based on EBSD characterization. Dislocation evolution realized the refinement of grains by promoting the transformation of dislocation walls/cell walls to high angle grain boundaries. The twin-twin/dislocation intersections were another important way of refinement. Strong <100> and <111> fiber textures were formed during drawing, which had the volume fractions of 24.9 % and 55.5 %, respectively, in the sample with true strain of 8.4. The <100> fiber texture was mainly associated with the twinning and dislocation slipping in the high Schmid factor condition, while the decrease in the fraction of <100> fiber texture was mainly attributed to the grain refinement. The wire peak-aged at 380 °C for 2 h achieved excellent comprehensive properties with yield strength of 1596 MPa, tensile strength of 1682 MPa and electrical conductivity of 15.5 %IACS.

Selective electron beam additive manufacturing of a nanoparticle-strengthened medium-entropy alloy for cryogenic applications

A strong, ductile medium-entropy alloy, MEA, (CoCrNi)94Al3Ti3 with few defects was fabricated using the selective electron beam additive manufacturing technique. Due to preheating the substrate at 1173 K, the as-printed MEA showed coherent L12 nanoparticles (dia.∼112 nm, volume fractioñ8.9 %) in 68 μm grains with a dual {100}<011> + {100}<001> texture. The as-built alloy exhibited a yield strength (YS) of 612 MPa, an ultimate tensile strength (UTS) of 1020 MPa, and an elongation to failure (ε) of 37 % at 298K. These values increased when testing was at 77 K, i.e. YS of 811 MPa, UTS of 1339 MPa, and an ε of 39 %. After tensile failure, the LAGBs and GND densities sharply increased at both temperatures to accommodate strain gradient along with <111> fiber texture. The lack of annealing twin boundaries led to a relatively low strain hardening rate (SHR) of 2500 MPa at 298 K and 3890 MPa at 77 K (at 5 % strain) as compared to values of thermo-mechanically processed (CoCrNi)94Al3Ti3. The SHR curves exhibited three distinct stages, where an abrupt upturn at an intermediate strain level can be attributed to the occurrence of DTs and SFs at 77 K, and the appearance of SFs at 298 K.

High strength and elongation of Mg-Gd-Nd-Zr alloy obtained by synergistic action of high-speed extrusion and short-time aging treatment

Magnesium–gadolinium (Mg–Gd)-based alloys have excellent high-temperature properties and the addition of two heterogeneous rare earth (RE) elements may promote the formation of secondary phase for better-strengthened properties. Herein, novel Mg-7Gd-2Nd-0.5Zr (wt%) alloys were prepared by synergistic reaction induced by high-speed extrusion (EX) and short-time aging treatment (AT). The microstructures, textures, and mechanical properties of the resulting alloys were then comprehensively studied by various analytical methods. The result reveals that the as-cast Mg-7Gd-2Nd-0.5Zr (wt%) alloy is composed of α-Mg matrix and Mg5(Gd,Nd) phase with bony and continuous networks at grain boundaries. The microstructure presents coarse deformed grains and fine recrystallized grains after high-speed EX, and formation of typical (0001)∥ ED extruded fiber texture and [1¯21¯1] RE texture is observed. The EX22 sample exhibits more Mg5(Gd,Nd) precipitated phases, fuller DRXed grains, and shorter peak aging times than the EX9 sample. After the AT at 250 °C, the proportion of deformed grains decreases due to static recrystallization, which leads to a reduction in the average grain size and weakening of the texture intensity. Therefore, combined effect of all strengthening mechanisms aids in achieving balance of high-strength and high-elongation for Mg-7Gd-2Nd-0.5Zr (wt%) alloy. The values of yield strength (YS), ultimate tensile strength (UTS), and elongation (EL) of EX22-A sample at room temperature are found to be 292.5 MPa, 350.6 MPa, and 24.3%, respectively. Overall, this study provides relevant experimental basis and theoretical guidance for the development of high-strength Mg-RE alloys, which are useful for future consideration.

Powder aerosol deposited calcium cobaltite as textured P-type thermoelectric material with power factors approaching single crystal values

In this work, the thermoelectric material calcium cobaltite Ca3Co4O9 (CCO), a promising p-type conducting thermoelectric oxide with anisotropic properties, was processed by the powder aerosol deposition method (PAD) to form a dense ceramic CCO film with a thickness in the µm range. The prepared films were characterized regarding their microstructure and thermoelectric properties between room temperature and 900 °C. After heat treatment at 900 °C, the CCO PAD film in-plane shows excellent properties in terms of electrical conductivity (280 S/cm at 900 °C) and Seebeck coefficient (220 µV/K at 900 °C). The calculated power factor in-plane (ab) reaches with 1125 µW/(m K2) 40 % of the single crystal value, surpassing the known-properties of CCO bulk ceramics. Examination of the microstructure shows a strong fiber texture of the film as well as a strong coarsening of the grains during the first heat treatment up to 900 °C.

Crystal plasticity finite element study on the microstructure and orientations evolution of {100} columnar grains in electrical steels

Most of the electrical steel slabs are composed of {100} columnar grains. After hot rolling, there is a texture gradient across the thickness. The surface shear textures (Goss texture{110}<100>, Brass texture{110}<112>, Copper texture{112}<111>) and certain <001>//ND fiber textures after hot rolling can be inherited into the finished sheet. The volume fraction and distribution of these textures after cold rolling significantly influence the magnetic properties. Therefore, a full-field crystal plasticity finite element method (CPFEM) was employed to simulate the evolution of microstructure and orientations of {100} columnar grains under plane strain compression and an additional displacement gradient component L13. Through qualitative and quantitative analysis of the simulated microstructure, it was found that under plane strain compression, {100}<110> grains were the most stable, followed by {100}<001> grains. Nearly {100}<021> orientation rotated towards {114}<481> orientation at the extremities of the simulation block. The additional displacement gradient component L13 enhanced the rotational effect. At the 45° shear direction and ends of the simulation block, the {110}<110> orientation originated from {100}<001> grains, the nearly {110}<112> orientation formed from {100}<021> grains, and the {112}<111> Copper orientation derived from {100}<110> grains. However, the simulation did not demonstrate the development of Goss shear orientation.

Manipulation of strength and ductility of AA5182-O through cyclic bending under tension and annealing processing

Aluminum alloy (AA) 5182-O sheets are processed by continuous bending under tension (CBT) followed by heat treatment to investigate microstructural changes for optimizing strength and ductility of the alloy. Bending depth and pull speed parameters of the CBT process are optimized to enhance the achievable strain beyond a conventional uniaxial tension, by inducing significant microstructural changes in the sheets. CBT processed samples are subsequently heat treated at various time-temperature regimes to determine the best recovery condition. The combination of CBT and heat treatment effect on the mechanical properties is examined by the subsequent uniaxial tension experiment. Measured microstructural changes in terms of grain structure and texture by electron backscattered diffraction (EBSD) show that it is possible to change a 〈001〉 cube texture typically present in rolled and annealed AA sheets into a 〈111〉 fiber texture by combining CBT and annealing processing. Moreover, measured mechanical responses reveal that a particular combination of CBT and heat treatment at 270 °C for 2 h can increase strength by over 75 % at the expense of 37 % reduction of uniform ductility. Interestingly, only a complete recrystallization after CBT restores the r-value of as-received material, while the intermediate heat treatment conditions lower the r-value.

Orientation dependent grain boundary precipitate distribution and the weakened pinning effects on domain walls in sintered Sm2Co17-type magnet

In a typical sintered multi-component Sm2Co17-type magnet with strong fiber texture, we show that the distributions of grain boundary precipitates (GBPs) are heavily dependent on the grain boundary (GB) geometry with respect to the texture direction, which has significant effects on domain wall pinning. Results demonstrate that the continuous GBPs turn into discrete upon the angle between {0001} planes and GB increases from 0° to 90°, meanwhile the GBPs thickness and precipitation free zones (PFZs) width both increase linearly by a factor of 2.5–4. Transmission electron microscopy (TEM) reveals that the GBPs are alternatively stacked Cu-rich SmCo5 and Zr-rich Smn+1Co5n−1 (n = 2,3,4) compounds, while the PFZs are composed of 2:17R and intermediate 2:17R’ phases. Atomic-level elemental mappings and first-principles calculations indicate that Cu exists at the Co-2c site in the SmCo5 forming SmCo3Cu2 and Zr locates at the dumbbell Sm-6c sites in the Smn+1Co5n−1. The symbiotic GBPs have orientation relationships of [0001]GBPs//[0001]2:17R and [101¯0]GBPs//[21¯1¯0]2:17R. The formation of anisotropic GBPs is owing to the strong fiber texture, i.e., the larger angle between {0001} planes and GBs, the more {0001} diffusion channels for atoms to GBs, resulting in discrete and thick GBPs. In-situ Lorentz TEM shows that the domain walls interrupted by GBPs migrate easily under applied magnetic fields. Possible approaches to enhance the magnetic hardness via tuning the GBs are proposed.

Microstructure evolution of interface and matrix during the preparation of SiCf/Ti60 composites

In this paper, continuous SiC fiber-reinforced Ti60 (SiCf/Ti60) composites were fabricated by preparing SiCf/Ti60 precursor wires from matrix-coated fibers and hot isostatic pressing (HIP) consolidation. The microstructures of the precursor wires and composites were investigated using XRD, SEM, EPMA, EBSD, and TEM, which led to the microstructure evolution of the composites. The conclusions of this study are as follows. 1. A reaction layer (RL) with a thickness of approximately 0.1 μm already exists at the interface of the precursor wires during the preparation. The HIP process accelerates the diffusion of the carbon coating with the Ti60 matrix, resulting in an increase in the thickness of the RL to approximately 0.5 μm. This layer is primarily composed of fine-grained TiC layer || discontinuous silicides || coarse-grained TiC layer. 2. The matrix of SiCf/Ti60 precursor wires contains α-Ti (∼ 1.9 μm), S2 (∼ 50 nm), and β-Ti (∼ 50 nm), in the matrix, β-Ti is precipitated from α-Ti, and HIP makes α-Ti, S2, and β-Ti grow to ∼ 2.4 μm, ∼ 200 nm, and ∼ 300 nm, respectively. 3. There are 〈0001〉//axial direction (AD) and 〈10−10〉//AD fiber textures in the matrix of the precursor wires, and HIP makes the matrix undergo a plastic deformation dominated by dislocation slip, and the pole density of the two kinds of textures are both increased.

Effect of HIP Treatment on the Evolution of Texture and Microstructure of LBPF Fabricated Pure Ni

Microstructure and texture analysis were conducted employing electron backscatter diffraction (EBSD) technique on laser powder bed fusion (LPBF) fabricated pure Ni. The texture analysis of the hot isostatic pressed (HIP) and as-printed (AP) samples were done utilizing orientation distribution function (ODF) maps. The AP sample comprises mostly of &amp;lt;110&amp;gt;||BD fiber texture with insignificant presence of twins. In contrast, the HIP sample has &amp;lt;111&amp;gt;||BD grains. It was found that the development of the texture &amp;lt;111&amp;gt;||BD was due to the deformation linked to the HIP process. In addition, HIP generated a substantial fraction of Σ3 coincident site lattice boundaries (CSL) because of pure Ni which is a medium stacking fault energy (SFE) element.

Preparing bulk nanocrystalline Cu–Al alloys via rotary swaging

Although nanocrystalline (NC) metals and alloys have been studied for nearly 40 years, their preparation is limited to the laboratory as large-scale; low-cost commercial production remains a challenge. In this study, high-strength bulk NC Cu–Al alloys were prepared from coarse-grained Cu–Al alloy rods via rotary swaging. Rotary swaging is characterized by the low cost and infinite length of the processed samples; therefore, it can advance the industrial application of bulk NC alloys. Core–shell-structured Cu–Al alloy rods with a hard NC core (diameter of 2.2 mm) wrapped in a soft ultrafine-grained (UFG) shell with a thickness of 1.75 mm were prepared using a rotary swage. Tensile tests revealed that the hard NC Cu–Al alloy core exhibited an ultimate tensile strength of 1034 MPa, which surpassed current strength records. Microstructural characterization showed that the hard NC core was composed of NC fiber grains with widths of 45 nm and lengths of 190 nm. The edge of the rod contained numerous low-angle grain boundaries and shear bands, which provided it with a lower strength and higher elongation than those of the center. During swaging, strong (200) and (111) fiber textures perpendicular to the cross-section were produced during the early stages of deformation. In the latter deformation stages, the polar densities of the (200) and (111) textures weakened, and some complex textures were formed along with high-angle grain boundaries. The grain refinement mechanisms were dominated by multiple deformation twinning, stacking faults, and dislocation slips. Finite elemental analysis showed that triaxial compressive stress and a high strain rate were applied to grain refinement. In addition, the softer shell protects the harder core during deformation, preventing fracture. This study verified an effective preparation technique for bulk NC materials via rotary swaging because it is a simple process with low cost and broad industrial prospects.

Influence of scanning speed on microstructures and mechanical properties of SLM produced Hastelloy X: as-built and solution-treated

Hastelloy X (HX) alloys with ideal strength and ductility match can be obtained by selective laser melting (SLM) and a proper follow-up heat treatment. This work studies the influence of scanning speed on grain size, grain boundary distribution, recrystallization and mechanical properties of as-built HX. These influences are reevaluated after a solution treatment at 1175 °C for 4h. The results reveal that the average grain size decreases, while the aspect ratio, texture intensity and the proportion of high-angle grain boundaries (HAGBs) increases with the increase of scanning speed. A small amount of recrystallization has occurred in the as-built alloys due to the cyclic thermal effect of SLM scanning. The finer grains and larger aspect ratio imply the higher energy storage during SLM, which will increase the recrystallizing nucleation rate. Solution treatment eliminates the fiber texture of 〈100〉//BD, significantly increases the HAGBs fraction and recrystallization fraction, reduces the grain aspect ratio, and coarsens the grains. With the increase of scanning speed, the strength of the Hastelloy X increases and the elongation decreases. The decrease of grain size is the main reason for the increase of yield strength.

Basic research on layered geopolymer composites with insulating materials of natural origin

New restrictions on carbon dioxide emissions and electricity consumption are currently being introduced around the world. Innovative solutions are being adopted in many countries to reduce CO2 emissions and material and energy consumption. The present work is related to the study of innovative binders based on geopolymers for the production of layered building envelopes. The binders are reinforced with composite bars and containing fibers of natural origin. The natural materials used to produce the samples are completely biodegradable. A 10-mol sodium hydroxide solution with an aqueous solution of sodium silicate was used for alkaline activation of geopolymers. The purpose of the study was to compare and determine the insulating properties of natural fiber-based materials such as coconut mat, jute felt, hemp felt, flax felt, flax wool, hemp wool, flax-jute wool, and to determine the effect of these materials on geopolymer composites, in which 4 layers of natural insulating materials were used, and the composites were reinforced by fiberglass bars. The publication presents the results of physicochemical studies of geopolymerization precursors and natural insulating materials, studies of thermal properties of fibers, mats, felts and wools, morphology of fiber structure and texture, as well as physical and thermal properties of finished multi-layer partitions. The results indicate the great potential of these materials in prefabrication and structural-insulation applications. The fabricated composites using 4 layers of natural fibers showed improved thermal conductivity by as much as 40% (reduced thermal conductivity from 1.36 W/m × K to about 0.8 W/m × K). The work may have future applications in energy-saving and low-carbon construction.

Effects of Konjac (Amorphophallus muelleri Blume) Flour Addition and Drying Time on the Crude Fiber and Texture Level of Instant Yellow Rice

Instant yellow rice is a traditional breakfast dish prepared using special technology for quick and practical cooking and a longer shelf life. Since rice has low crude fiber content as the main ingredient, substitution with local sources, such as konjac flour, can be made. Konjac flour is the powdered root of konjac plant, and it contains high crude fiber. Therefore, this study aimed to examine the texture and crude fiber properties of instant yellow rice with the addition of konjac flour. Furthermore, a completely randomized design (CRD) was used with two factors, namely variations in konjac flour concentration (2%, 3%, and 4%) and variations in drying time (5 hours, 6 hours, and 7 hours). Each sample was analyzed for the physical (hardness, stickiness and chewiness texture) and chemical characteristics (crude fiber content). The results showed that the konjac flour concentration had a significant (p&lt;0.05) effect, while the drying time had no significant (p&lt;0.05) effect on the physical and chemical characteristics of instant yellow rice. Therefore, 5 hours of drying might be enough for the rice processing. The addition of 2% konjac flour on instant yellow rice dried for 5 hours showed 2.48±0.50 a N of hardness texture, 5.53±0.07 c N stickiness texture, 4.59±0.02 a N chewiness texture, and 5.20% of crude fiber. Addition of 3% konjac flour on instant yellow rice dried for 5 hours showed 5.74±0.08 b N of hardness texture, 4.73±0.17 b N stickiness texture, 4.37±0.05 a N chewiness texture, and 5.20% of crude fiber. The addition of 4% konjac flour on instant yellow rice dried for 5 hours showed 6.41±0,02 c N of hardness texture, 4.06±0.70 b N stickiness texture, 3.33±1.52 a N chewiness texture, and 5.35% crude fiber. This showed the best treatment was the use of instant yellow rice with 4% konjac flour addition at 5 hours drying time.

Integration Of Solution‐Processed BaTiO3 Thin Films with High Pockels Coefficient on Photonic Platforms

AbstractThe heterogeneous integration of ferroelectric BaTiO3 thin films on silicon (Si) and silicon nitride (SiN)‐based platforms for photonic integrated circuits (PICs) plays a crucial role in the development of future nanophotonic thin film modulators. Since the electro‐optic (EO) properties of ferroelectric thin films strongly depend on their crystal phase and texture, the integration of BaTiO3 thin films on these platforms is far from trivial. So far, a conventional integration route using a SrTiO3 template film in combination with high vacuum deposition methods has been developed, but it has a low throughput, is expensive and requires monocrystalline substrates. To close this gap, a cost‐efficient, high‐throughput and scalable method for integrating highly textured BaTiO3 films is needed. Therefore, an alternative method for the integration of highly textured BaTiO3 films using a La2O2CO3 template film in combination with a chemical solution deposition (CSD) process is presented. In this work, the structural and EO properties of the solution‐processed BaTiO3 film are characterized and its integration into an optical ring resonator is evaluated. The BaTiO3 film exhibits a fiber texture, has a large Pockels coefficient (reff) of 139 pm V−1, and integration into a ring resonator‐based modulator shows a VπL of 1.881 V cm and a bandwidth of &gt; 40 GHz. This enables low‐cost, high‐throughput, and flexible integration of BaTiO3 films on PIC platforms and the potential large‐scale fabrication of nanophotonic BaTiO3 thin‐film modulators.

Nanostructuring of an additively manufactured CoCrFeNi multi-principal element alloy using severe plastic deformation: Comparison of two materials processed by different laser scan speeds

Experiments were conducted to reveal the refinement of the microstructure and the evolution of the hardness of an additively manufactured (AM) CoCrFeNi multi-principal element alloy (MPEA) processed by severe plastic deformation (SPD) using high pressure torsion (HPT) technique. AM was carried out by laser powder bed fusion (L-PBF) technique at two different laser scan speeds. The as-built alloys for both laser scan speeds have a single-phase face-centered cubic (fcc) structure with <110> fiber texture parallel to the building direction. X-ray line profile analysis (XLPA) revealed that the dislocation density was considerably high even in the AM-processed state before HPT (3 × 1014 m−2) which increased by two orders of magnitude during HPT. The saturation of the lattice defects (dislocation density and twin fault probability) as well as the crystallite size occurred at a shear strain of about 10 during HPT. In both AM-processed alloys, <111> fiber texture developed parallel to the normal of the HPT-processed disks. For both laser scan speeds, the initial grain size in the AM-processed samples was refined from 70 to 90 μm to the nanocrystalline regime after 10 turns of HPT. Additionally, nanotwins formed with a probability of about 3 %. The initial hardness of the AM-processed MPEA samples for both laser scan speeds was 2700–2800 MPa, which is superior to that of CoCrFeNi produced by casting (about 1380 MPa). This can be explained by the high dislocation density in the AM-processed specimens. The formation of nanostructure with high lattice defect density during HPT resulted in a very high hardness value of about 5500 MPa in the AM-processed CoCrFeNi MPEA samples for both laser scan speeds.

The thermal stability and degradation mechanism of Cu/Mo nanomultilayers

ABSTRACT The microstructural evolution of Cu/Mo nanomultilayers upon annealing was investigated by X-ray diffraction and transmission electron microscopy. The isothermal annealing process in the temperature ranges of 300–850°C was conducted to understand the thermal behavior of the sample and follow the transformation into a nanocomposite. Annealing at 600°C led to the initiation of grain grooving in the investigated nanomultilayer, and it degraded into a spheroidized nanocomposite structure at 800°C. The sample kept the as-deposited Cu {111}//Mo{110} fiber texture up to 850°C. The residual stress was investigated to explain microstructure changes. The activation energy of degradation kinetics of Cu/Mo nanomultilayers was determined to understand the rate-determining mechanism for the degradation of nanolaminate structures.

Microstructural evolution in 12% Cr heat-resistant steel during compression deformation at 650°C

Microstructural evolution in 12% Cr heat-resistant steel during compression deformation at 650°C

Multimethod cross-sectional characterization approaching the limits of diamond monophase multilayers

Chemical vapour deposited diamond draws significant scientific interest due to its wide range of mechanical and functional properties, which can be easily tuned by the applied deposition conditions. Here, hot filament chemical vapour deposition was used to synthesize four monophase multilayer diamond thin films with individual layer thickness down to ∼ 300 nm. Extensive structural characterization by scanning electron microscopy and Raman spectroscopy on the cross-section confirmed the different diamond morphologies originating from the different applied process parameters of the individual sublayers, where Raman spectroscopy could give a clear distinction between nano- and microcrystalline diamond down to a layer thickness of ∼ 1 μm. Cross-sectional X-ray nanodiffraction identified exclusively the diamond crystal structure throughout the cross-section of the multilayered diamond thin films. Cross-sectional phase and FWHM analysis allowed to discriminate between the diamond morphologies down to ∼ 500 nm, thus identifying the limitations of monophase diamond multilayers. While the microcrystalline diamond sublayers all exhibit pronounced structural gradients expressed in (i) increasing intensity of the 111 Debye-Scherrer ring, (ii) ⟨110⟩ fibre texture, and periodic variations of (iii) grain size and (iv) residual stress, the nanocrystalline diamond sublayers showed no pronounced cross-sectional variations. In summary, the experimental results provide insights into the cross-sectional evolution of microstructure and residual stress and the limitations of monophase multilayered diamond thin films.

Anomalous ductility-strength synergy occurred after cold rolling in a high Gd content Mg alloy

During cold rolling in magnesium (Mg) alloys, there will always be serious ductility deterioration, which greatly restricts the application of this processing method. In this work, ductility-strength synergy occurred after cold rolling was carried out on a 〈0001〉 fiber textured Mg-17.5Gd-Zr alloy (wt.%). The ductility-strength synergy can be mainly attributed to texture randomization, microstructure refinement, and easier basal slip transfer condition in the twinned grains. Firstly, the activation of multiple twinning behaviors, i.e., {10−12}, {10−11}, and {11−21} twinning, and related twin-twin interaction restrict the formation of strong basal texture and facilitate the texture randomization. Secondly, profuse high-angle grain boundaries form through dislocation-twin interaction, twin-twin interaction, and dislocation interaction, which promote microstructure refinement. Thirdly, the basal slip transfer becomes easier in the twinned grains owing to the activation of multiple twinning behaviors and their impingements. Activation of {11−21} twinning and 〈c + a〉 dislocations and the 〈0001〉 fiber texture which is favorable for multiple twinning activating during cold rolling are considered to be the key roles for microstructure and texture optimization.