Pole Figure Analysis Research Articles

Anisotropy of acoustic properties in thin-sheet rolled low-carbon manganese steel

Thin-sheet rolled low-carbon manganese steel 09G2S with a thickness of 0,8 mm which has strong property anisotropy due to texture and residual stresses, was experimentally studied using SH-wave with horizontal polarization and zero-order symmetric Lamb wave mode. The velocities of elastic wave propagation along the sheet were analyzed as their direction and polarization varied relative to the rolling direction in the range of angles from 0 to 180 degrees. The excitation and reception of normal waves in the sheet were carried out by piezoelectric transducers with dry point contact, providing tangential force application. The results of the research on the anisotropy of acoustic properties, X-ray structural analysis of residual stresses and inverse pole figures, and metallographic studies were obtained.

New insights into selective leaching and ferritization in 15-15Ti austenitic steel in lead-bismuth eutectic through parent phase reconstruction

Selective leaching accompanied by ferritization is widely observed in the dissolution corrosion of austenitic steels exposed to lead-bismuth eutectic. This study proposes a refined mechanism for selective leaching involving solid-state diffusion followed by dissolution-reprecipitation processes. Pole figure analysis reveals that ferritization follows the Nishiyama-Wassermann orientation relationship, independent of corrosion environment or corrosion behavior. Moreover, austenite reconstruction analysis shows that the growth of ferrite is hindered by the misfits at random high-angle grain boundaries. Hence the above results suggest that ferritization is initially driven by solid-state diffusion. As LBE channels open within the grains, further growth of ferrite is assisted by the dissolution-reprecipitation mechanism. Additionally, the formation of dual-oriented ferrite grains at Σ3 twin boundary is observed, and the selectivity of this formation with respect to grain boundary and ferrite orientation is discussed.

Microstructural analysis of titanium alloys based on high-temperature phase reconstruction

The microstructural evolution of titanium alloys under high-temperature conditions plays a key role in determining their mechanical properties and hot working behavior. This research presents an advanced method for calibrating β phase reconstruction software using in situ testing on Grade 2 titanium, which achieves accurate reconstruction of the parent β phase microstructure. In addition, unique microstructural observations in the forging of Ti-6246 titanium alloy are highlighted, demonstrating the influence of deformation parameters on the resulting β phase grain structures. Using advanced techniques such as electron backscatter diffraction and Burgers orientation relationship-based software, the research elucidates the behavior of these phases under varying thermal and deformation conditions. In Grade 2 titanium, significant grain growth and phase transformation dynamics were observed upon heating beyond the β-transus temperature during in situ calibration of β phase reconstruction software. The analysis demonstrates the effectiveness of the software in precise reconstructing the parent β phase microstructure based on the orientation of the inherited αs phase. Furthermore, the evaluation of hot forming parameters in Ti-6246 alloy shows the influence of deformation temperature and strain rate on the resulting microstructure. Finite element method analysis coupled with dynamic material modeling elucidates the distribution of temperature, strain rate, and effective strain during forging, which aids in the qualitative assessment of hot workability. Microstructural observations in Ti-6246 alloy forging highlight the presence of elongated colonies of αs phase precipitates, indicative of localized strain intensities and deformation temperatures. In addition, EBSD analysis coupled with β phase reconstruction reveals distinct microstructural features in different regions of the forging. In particular, regions subjected to higher strain rates exhibit elongated β phase grains with pronounced disorientation gradients, suggesting intense deformation. Conversely, optimal forging conditions lead to the appearance of unreinforced axisymmetric β phase grains, indicating dynamic recovery processes. Pole figure analysis further emphasizes the Burgers crystallographic relationship between the αs and β phases, confirming that deformation during forging occurs exclusively within the β phase. These results provide valuable insights into the microstructural evolution in titanium alloys under high-temperature conditions, which are essential for optimizing hot working processes and improving mechanical properties.Graphical abstract

Orientation relationship between TiFeH and TiFe phases in AB-type Ti–Fe–V–Ce hydrogen storage alloy

The partially hydrogenated microstructure of an AB-type Ti–Fe–V–Ce hydrogen storage alloy was investigated using scanning electron microscopy (SEM) with electron backscatter diffraction (EBSD). For the first time, the formation of the orthorhombic β-TiFeH phase was directly observed by using SEM-EBSD. Lamellar structures consisting of TiFeH and body-centered cubic TiFe phases with a (100)TiFeH∥(100)TiFe habit-plane pair were observed. Pole figure analysis was performed to confirm the orientation relationship between the TiFeH and TiFe phases to be [011](100)TiFeH∥[010](100)TiFe. The formation of TiFeH was characterized by simple lattice expansion with a short-range arrangement of H atoms and surface relief. In addition, unidirectional microcracks along the (100)TiFe planes were observed, presumably owing to the dehydrogenation of the TiFeH phase.

Correlation of microstructure, texture, and mechanical properties of friction stir welded Joints of AA7075-T6 plates using a flat tool pin profile

This study investigates the influence of square and hexagon tool pin profiles on the butt joint of AA7075-T6 plates through friction stir welding. In contrast to the AA7075-T6 base metal with a grain size of 32.736 μm, both square (4.43 μm) and hexagon (5.79 μm) pin profiles led to a significant reduction in grain size within the stir zone (SZ) of the weld cross-section. The SZ region exhibited a gradient in recrystallization and a notable fraction of high angle grain boundaries, attributed to continuous dynamic recrystallization influenced by variations in temperature and strain rate. Pole figure analysis revealed predominant shear texture elements (B/ B‾ and C) with minor A1*/A2* and A/ A‾, indicating elevated strains within the SZ. Orientation distribution function (ODF) analysis identified recrystallization texture elements such as Goss {110} <001>, cube {001} <101>, and P {011} <112>, along with shear texture components F {111} <112> and rotating cube (H) {001} <110>. Tensile and nanoindentation analyses demonstrated that the weld joint using a square-shaped pin profile exhibited higher strength, elongation, and elastic modulus compared to other weld joints. These findings suggest that the square tool pin geometry enhances material flow and grain refinement during welding, thereby improving the mechanical properties of the joint.

Heterogeneous microstructure development in additive friction-stir deposited Al-Mg-Si alloy

Aluminum alloy 6061-T6511 was printed by additive friction stir deposition onto a cast aluminum A206-T4 plate. Metallography, X-ray powder diffraction, X-ray pole figure analysis, and electron backscatter diffraction of the center, advancing side, and retreating side of the 6061 deposit reveals different texture and grain structure characteristics across the transverse direction and through each layer. These distinct microstructural domains are indicative of spatially varied temperature, strain rate, and strain accumulation during deposition, and consequently of regions differing in the fraction of dynamic recovery and dynamic recrystallization during deposition. Hardness mapping over the complete cross section at 0.75 mm resolution shows the alloy continues to age after active deposition, and hardness increases over the 5 mm nearest the final printed layer. Additional mapping at 0.10 mm resolution shows intralayer hardness variations of the deposit on the retreating side. These observations demonstrate that complex and non-uniform thermal-mechanical transients occur during additive friction stir deposition, resulting in spatially non-uniform microstructure and properties.

Superplastic-like flow behavior in Al0.2CoCrFeNiMo0.5 high entropy alloy

High temperature tensile experiments were performed on Al0.2CoCrFeNiMo0.5 high entropy alloy in the temperature range of room temperature (RT) to 900 °C. It exhibited good resistance to softening up to 700 °C, and thereafter a rapid decrease in the strength was observed. Superplastic-like tensile elongation of ∼ 275 % was observed at a strain rate of 1x10-3 s−1 and at a temperature of 900° C. Tensile experiments at different strain rates along with strain rate jump experiments at 900 °C showed a strain rate sensitivity of ∼ 0.32. Kernal Average Misorientation (KAM) maps at the gauge and grip portions along with texture pole figure analysis suggesting that dislocation glide might be the active deformation mode responsible for large tensile elongation. Cavitation along the secondary phase-matrix interphase was the dominant failure mode.

Surface scattering-dependent electronic transport in ultrathin scandium nitride films

With the constant miniaturization of device technologies, it has become essential to understand and engineer the electronic properties of semiconductors in nanoscale dimensions. Scandium nitride (ScN), an emerging rock salt indirect bandgap semiconductor, has attracted significant interest for its interesting thermoelectric, plasmonic, neuromorphic computing, and Schottky barrier device applications. However, an in-depth understanding of the electronic transport, carrier scattering mechanism, and optical properties in ultrathin ScN films is still missing. Here, we show surface-scattering dominant electronic transport in epitaxial ScN films at nanoscale thicknesses. At the ultrathin dimensions, surface scattering increases significantly due to the large surface-to-volume ratio and growth-induced texturing. As a result, mobility decreases, and resistivity increases drastically with decreasing film thickness. Temperature-dependent electronic transport shows that the mobility of the ultrathin films decreases with increasing temperature due to the ionized-impurity and dislocation scattering. Electronic transport properties are further rationalized with x-ray diffraction and pole-figure analysis that shows that while the ultrathin films maintain their predominant 002 texture, their quality degrades with decreasing thickness. However, no significant changes are observed in the electronic structure of the films, as evidenced by x-ray photoelectron spectroscopy, photoemission measurements, and first-principles density functional theory calculations. Our results elucidate the impact of surface scattering on the ultrathin ScN films and would lead to miniaturized devices with improved efficiencies.

Growth and optical properties of NiO thin films deposited by pulsed dc reactive magnetron sputtering

NiO thin films with varied oxygen contents are grown on Si(100) and c-Al2O3 at a substrate temperature of 300 °C using pulsed dc reactive magnetron sputtering. We characterize the structure and optical properties of NiO changes as functions of the oxygen content. NiO with the cubic structure, single phase, and predominant orientation along (111) is found on both substrates. X-ray diffraction and pole figure analysis further show that NiO on the Si(100) substrate exhibits fiber-textured growth, while twin domain epitaxy was achieved on c-Al2O3, with NiO(111)∥Al2O3(0001) and NiO[11¯0]∥Al2O3[101¯0] or NiO[1¯10]∥Al2O3[21¯1¯0] epitaxial relationship. The oxygen content in NiO films did not have a significant effect on the refractive index, extinction coefficient, and absorption coefficient. This suggests that the optical properties of NiO films remained unaffected by changes in the oxygen content.

DC Saçtırma Metoduyla Üretilmiş Çift Katmanlı Mo İnce Filmlerin Yarı Kantitatif Doku Analizinin Yapılması ve Kutup Figürlerinin Araştırılması

Molibden (Mo) malzemesi benzersiz özellikleri sayesinde birçok farklı alanda kullanılmaktadır. İnce filmlerin doku analizleri sayesinde katmanlar arası arayüz durumlarının uyumluluğu araştırılmaktadır. Üretim parametrelerine ve sonrasında yapılan işlemlere göre filmlerin dokuları değişebilmektedir. Bu sebeple kullanım alanına bağlı olarak en uygun dokuya sahip Mo ince filmlerin üretilmesi için ideal üretim parametrelerinin belirlenmesi gerekmektedir. Bu çalışmada, CIGS güneş gözesi uygulamalarında sıklıkla istenen BCC yapısında ve (110) düzlemindeki Mo ince filmler üretilebilmiştir. Üretim, Mo filmin alttaş yüzeyine tutunumunu ve elektriksel iletkenliğini iyileştirmek için çift katmanlı üretim stratejisi kullanılarak gerçekleştirilmiştir. Üretilen filmlerin SEM, AFM ve XRD sistemleri ile yüzey, topoğrafya ve yapı analizleri gerçekleştirilmiş ayrıca yarı kantitatif doku analizleri yapılarak kutup figürleri elde edilmiştir. Topoğrafik ve detaylı yapısal analiz sonuçları birbirleri ile ve literatürde var olan diğer çalışmalar ile kıyaslandığında bu çalışmada ortaya koyulan üretim parametrelerinin kullanılabilirliği gösterilmiştir.

Electrorecrystallization of Invar 36 alloy

The recrystallization of the Invar 36 alloy after current stressing, at 8000–18000 A/cm2, was investigated with X-ray diffraction, electron back scattered diffraction and magnetic hysteresis. The electrical resistivity of the alloy increased by 10 % after electrical current stressing, while the microhardness did not show significant change. The average grain size was slightly refined, yet the grain size uniformity was improved by current stressing. The crystal orientation map shows the transition trend from (001) to (101) after current stressing. The pole figure analysis indicated that the Cube texture and the annealed twin were degraded after current stressing. Current stressing resulted in the transition of the Cube texture to Copper texture. The magnetic hysteresis analysis showed the structure did not exhibit much change to influence the coercive force. The increase in electrical resistivity was ascribed to the variation in texture and the possible increment of dislocation density as indicated by the Kernel Average Misorientation and X-ray diffraction results.

X-ray Pole figure analysis for orienting TGSM grown bulk ZnTe crystal for Terahertz device applications

X-ray Pole figure analysis for orienting TGSM grown bulk ZnTe crystal for Terahertz device applications

MoS2 -Mediated Epitaxial Plating of Zn Metal Anodes.

Metal-based anodes (Li, Zn, etc.) are regarded as promising solutions for next-generation advanced batteries due to their high theoretical specific capacities. However, most of these metal anodes suffer from dendrite growth, which severely restricts their practical applications. Recently, epitaxial anode metal deposition by choosing a suitable substrate has received tremendous attention as an effective strategy to suppress dendrites. However, the epitaxial relationship between plated metal and the substrate has been a subject of debate. Herein, large-area, mono-orientated 2D material (MoS2 ) is used, for the first time, to electrodeposit truly epitaxial Zn anodes. The continuous (without edges) mono-orientated MoS2 films are shown to be an effective strategy for suppressing metal dendrites. In addition, the epitaxial nature of the electrodeposited Zn anode is proven by pole figure analysis, which provides the first demonstration of truly epitaxial Zn anode growth over large area as metal anode protection strategy through epitaxy.

Post-building successive treatments using surface laser remelting and ultrasonic nanocrystalline surface modification for rough surface built via directed energy deposition

In this study, surface laser melting (SLR) and ultrasonic nanocrystalline surface modification (UNSM) were applied as post-building treatments to modify the surface of additively manufactured parts via directed energy deposition (DED). The DED building of STS316L powder was conducted on a substrate, and the deposited surface was irradiated with a laser of the DED equipment to perform SLR on the surface. Subsequently, the remelted surface was re-treated with UNSM, and the changes in each step were examined. Via the experiment, the as-built surface roughness and waviness of 12.5-μm Ra and 8.22-μm Wa, were improved to 2.3 μm and 2.5 μm, respectively, by the successive treatments of SLR and UNSM (denoted by SLRed-UNSMed). From the perspective of grain refinement by UNSM treatment, performing SLR with a small overlap followed by UNSM was determined to be effective in maximizing the effect of UNSM. The SEM and EBSD analysis results indicated that grain refinement occurred in a deeper region in SLRed-UNSMed than in the sample (denoted by UNSMed) that was treated solely with UNSM and no SLR. In addition, according to the pole figure analysis, the primary surface modification and grain reorientation in the (100) direction by SLR allowed the UNSM energy to be transferred more evenly and deeper. Meanwhile, high hardness and compressive residual stress were observed in SLRed-UNSMed, and a nano-indentation test confirmed an increase in the effective depth of UNSM relative to that of UNSMed. Based on this study, an SLR treatment followed by UNSM can be expected to achieve surface modification and improve the mechanical properties of additively manufactured products.

A universal shear-lag model for accurate assessment of whisker load-transfer strengthening in metal matrix composites

Accurate assessment of the strengthening contribution of whiskers is crucial for the design, development, and application of high-performance whisker reinforced metal matrix composites (WRMMCs). The present work presents a novel universal shear-lag model to accurately calculate the load-transfer strengthening of whiskers in all WRMMCs regardless of matrix and reinforcement. This model considers the tensile strength of whiskers and the stress transfer from the matrix to the whisker ends. The present model provides a facile way to allow consideration of the influence of whisker orientation and aspect ratio distributions on whisker load-transfer strengthening by introducing probability density functions. Their distribution characteristics have a significant effect on the predicted results, which cannot be simply replaced by their average values. The present model was verified by the reported experimental results and comparison with other models, and it shows better agreement. Moreover, titanium matrix composite reinforced with misaligned TiB whiskers was prepared by vacuum arc remelting and hot-forging. TiB whisker aspect ratio and orientation distributions were quantified by image statistics and pole figure analysis. The anisotropy of yield strength was evaluated under monotonic tensile loading in various directions of the composite. Different shear-lag models were applied to evaluate the load-transfer strengthening of TiB whiskers at different angles relative to the tensile loading direction. The present model gave a more accurate prediction of the anisotropy of yield strength than other shear-lag models.

Exploiting different morphologies of non-ferromagnetic interacting precursor’s for preparation of hexaferrite magnets

Sintered cold compacted hexaferrite magnets with appreciable magnetic properties and crystallite alignment were made from non-magnetic precursors without applying an external magnetic field. This work presents a novel approach employing non-ferromagnetic interacting precursors comprising of platelet shaped six-line ferrihydrite and needle shaped goethite nanoparticles. A hydrothermal synthesis route was employed to produce platelet shaped six-line ferrihydrite of ~5 nm thickness. Needle shaped goethite nanoparticles were likewise prepared by hydrothermal synthesis with apparent dimensions of ~10 × 27 × 10 nm 3 extracted from X-ray powder diffraction data. The powder diffraction Rietveld modelling also revealed the presence of an amorphous phase in the six-line ferrihydrite and a SrCO 3 impurity. The presence of needle shaped goethite nanoparticles improves the alignment of magnets, while retaining the coercivity ( H c ), in contrast to hexaferrite magnets prepared from six-line ferrihydrite by spark plasma sintering (SPS). The non-ferromagnetically interacting precursors were directly converted to the SrFe 12 O 19 magnets by pressing them with conventional compaction technique followed by subsequent sintering of the pellets. Decoupling the pressing and sintering step is interesting for industrial production of magnets. The hexaferrite magnets prepared displayed good combination of saturation magnetization M s = 70 Am 2 /kg and coercivity H c = 297 kA/m with some degree of alignment of the crystallites M r / M s = 0.71. This procedure exploits the anisotropic shape of the crystallites and compaction using uniaxial pressure followed by sintering into aligned bulk magnets. Two sets of hexaferrite bulk magnets were prepared by sintering at 900 °C and held for 2 h and 1050 °C with a holding time 0 min. The hexaferrite magnets sintered at 1050 °C were subjected to transmission pole figure analysis. The texture index for each pellet were extracted from the pole figure analysis. Employing needle shaped goethite nanoparticles actually enhanced the alignment of the hexaferrite magnets. The magnet obtained from only six-line ferrihydrite displayed only a slightly improved texture index when compared with mixture of six-line ferrihydrite and goethite nanoparticles. • Two different morphologies comprising platelets and needles were employed in synthesizing SrFe 12 O 19 magnets. • Simple conventional compaction were performed to produce highly aligned SrFe 12 O 19 magnets. • This method requires no magnetic field to align the crystallites along the easy axis. • Magnet with saturation magnetization, M s of 70 Am 2 /kg and coercivity H c of 297 kA/m with 18 kJ/m 3 were produced.

Microstructure, magnetic domain and dynamic loss of surface-textured Fe-based nanocrystalline alloy

1 DO 3 dendritic-crystallites bear <001>-oriented fiber texture at free surface. 2 TFA slightly weakens the fiber texture and induces magnetic rotation process. 3 The surface-textured alloy after TFA exhibits low dynamic loss. 4 A correlation mechanism between microstructure, domain and loss was obtained. Heterogeneous coarse surface crystallites induced in the industrial Fe-rich nanocrystalline alloy is an obstacle for high-frequency and high-power commercial applications. Herein, the phase, crystal orientation, nanostructure and magnetic domain evolution of the surface-crystallized Fe-rich alloy were systematically investigated. Microstructure and inverse pole figures analysis confirms that the DO 3 ordered dendritic-crystallites bear <001>-oriented fiber texture before and after annealing at the free surface, while ultrafine nanocrystals are randomly oriented in the interior and wheel surface after annealing. As compared to zero magnetic-field-annealing, the transverse magnetic-field-annealing induces weakly oriented fiber texture and relatively uniform dendritic-crystallites at the surface, and uniform anisotropy in the interior and surface, which promotes smooth wall motion at the surface and magnetization rotation in the interior. This synergetic effect reduces the excess loss and leads reduction in dynamic loss at 1.0 T and 10 kHz by 36%.

The effect of orientation and pore size on nano mechanical behaviour of Ag thin films: a comparison between experiment and atomistic simulation

ABSTRACT This paper describes the thickness-dependent texture evolution during annealing in Ag thin films, commonly used in micro and nano-devices. The effect of porosity and crystal orientation on mechanical properties for the films deposited by the magnetron sputtering method is particularly addressed using nano-indentation experiment and atomistic simulation. X-ray pole figure analysis revealed that the films exhibited sharp fibre texture with a major <1 1 1> component accompanied by minor twin components of <5 1 1> and <5 7 13> and a weak component of <1 0 0>. The mechanical behaviour of the films was investigated experimentally using a Berkovich tip to measure the hardness (H) and modulus of elasticity (E) at each individual grain and porous region. The average Young’s modulus of strongly oriented [1 1 1] grain at porous and non-porous regions is estimated to be 44 ± 7 and 67 ± 5 GPa. Molecular Dynamics simulations have been performed on (1 1 1), (1 1 0), (0 0 1), (5 1 1), and (5 7 13) surfaces of Ag single crystal using a spherical indenter to investigate the anisotropic nature of hardness and elastic modulus from the Load∼Indentation depth curves. The mechanical properties of [1 1 1] oriented single crystal in the presence of a sub-surface void have been studied. Our results have demonstrated that the void acts as an efficient absorber of dislocation limiting the extension of the plastic zone. The simulated modulus of elasticity (E: 54.2 GPa) results obtained at a temperature of 300 K in the presence of a void are compared with experimentally measured values with a variation of around 6%.

Textural development, martensite lath formation and mechanical properties variation of a super strength AISI4340 steel due to austenitization and tempering temperature changes

In this investigation, the textural development, as well as martensite lath formation on the microstructural changes and mechanical properties variation of a super strength AISI 4340 was studied under different austenitization and tempering conditions. To study the influence of tempering temperature, austenitization temperature of 900 °C was followed by tempering in the range of 200–425 °C on the sheet samples. As well, to investigate the effect of austenitization temperature, austenitization temperature of 850–1200 °C was followed by rapid quenching and tempering at 200 °C. Microstructural investigations were conducted using optical microscopy (OM), field emission scanning electron microscopy (FE-SEM) that was equipped with the electron backscattered (EBSD) as well as energy dispersive spectroscopy (EDS) detectors, X-Ray diffraction (XRD), and transmission electron microscopy (TEM). In addition, mechanical properties were evaluated using tensile testing, macro-hardness testing, and Charpy impact testing. Results showed that increasing austenitization temperature up to 950 °C increased ductility which was followed by a sharp drop as the austenitization temperature increased thereafter. Also, it was found that increasing the austenitization temperature from 850 to 1200 °C decreased yield strength (Y.S), and ultimate tensile strength (U.T.S) for about 24%, 26%, respectively. It reduced impact energy by about 35%. Such reductions were related to the increased mean diameter of the prior austenite grain size from 2 μm for the former temperature to 110 μm in the latest temperature. EBSD analysis showed that the steel texture was mostly randomized at high austenitization temperature. (100) pole figure analysis showed that Cube ({100} 〈001〉) and Copper ({112} 〈111〉) components were developed during the optimized heat treatment of 900 °C followed by tempering at 200 °C. PF analysis also indicated that the texture intensity was weakened at lower austenitization temperatures. The presence of the Copper component at the very low austenitization temperature could explain the low ductility of this scenario. Orientation distribution function (ODF) analysis showed that the Cube component was dominant, and the Copper component severely weakened, during the optimum austenitization temperature, which would explain the optimum mechanical properties combinations, particularly ductility. Finally, the mentioned optimized route provided Y.S of 1720 MPa, U.T.S of 1900 MPa, El% of 11%, and Impact energy of 44 J, which confirmed the development of super-strength steel.

Effect of geometrically necessary dislocations induced strain on the corrosion behavior of Ni coatings with different surfactants

Ni coatings were electrodeposited using surfactants of different polarities. Pole figures analysis showed similar surface texture ({110} surface plane) for all coatings. Coating with cationic (CTAB) surfactant contained the highest fraction of low energy low angle grain boundaries (LAGBs) but showed the highest corrosion rate due to geometrically necessary dislocations (GNDs) distribution. GNDs in coating with cationic surfactant promoted high grain orientation spread (GOS) values, suggesting increased coating strain. Coatings with anionic (SLS) surfactants showed higher corrosion resistance than other coatings because of the presence of GNDs as strings along the boundaries, which yielded lower coating strain.