Growth Texture Research Articles

Effect of thermal cycling on microstructure and mechanical properties of 2A97 Al–Li alloy fabricated by direct laser deposition

Direct laser deposition (DLD) is a potential approach to prepare large-scale metal component. This work focuses on understanding microstructural characteristics and mechanical properties along deposition direction of 2A97 Al–Li alloy fabricated by direct laser deposition. As-deposited sample showed coarse equiaxed grains at top and columnar crystals at middle and bottom. Growth texture of as-deposited sample along <001> was relatively obvious, value of which increased first and then decreased from bottom to top. Thermal cycle led to different kinds and distribution of precipitated phases along deposition direction, which affected microhardness and tensile strength. T1 phase and a small amount of T2, TB phase precipitated at top. Effect of thermal cycle from top to bottom gradually increased, resulted in δ′, T2, TB phase coarsened. As a result, microhardness decreased from top (99 HV) to bottom (75HV). The sample in bottom showed an ultimate tensile strength (UTS) of 232.9 ± 4.3 MPa, and elongation of 9.5 ± 1.4%. While, ultimate tensile strength was increased to 268.5 ± 5.2 MPa, and elongation was 12.5 ± 0.9% in middle part, which was close to that of sample at top.

Effect of electrodeposition parameters on the evolution of crystallographic texture and internal stress of Ni/ZrC composite coatings

Crystallographic texture and internal stress are two important aspects of microstructures, responsible for various physical and chemical properties of electrodeposited composite coatings. This paper aims to understand how preparation parameters such as current density, size and concentration of second-phase particles, particularly deposition time, influence the crystallographic texture and internal stress of electrodeposited Ni matrix composites. The results show that the evolution of surface morphology, crystallographic texture and the internal stress of electrodeposited Ni/ZrC composites is strongly related to the content of incorporated ZrC in coatings, which increases after an increase in the amount of ZrC particles loaded in the electrolyte, from 0 g/L to 40 g/L, and from a decrease in applied current density, from 20 A/dm2 to 1.25 A/dm2. By increasing the ZrC content in coatings, the crystallographic texture of Ni/ZrC is depressed and internal stress is modified from 329.48 MPa to 56.71 MPa. During electrodeposition, the exhibited texture changes from <111> initial texture to <100> growth texture for pure Ni coatings, and to random orientation for Ni/ZrC coatings. The tensile internal stress of Ni/ZrC decreases, followed by a gradual increasing with an increase of thickness. ZrC nanoparticles incorporation results in Ni/ZrC coatings with a weaker texture and lower internal stress than Ni/ZrC coatings that incorporate ZrC micron particles.

Origin of multilayer corona textures in mafic granulites from the Sandmata Complex, Aravalli Craton (northwestern India): petrological characteristics and tectonic implications

In Late Proterozoic mafic granulites of the Sandmata Complex in Rajasthan, northwestern India, multilayer corona textures were formed along the interface between orthopyroxene and plagioclase. We examined the metamorphic conditions and processes of formation of these coronae, which provide an insight into the interplay between steady state and sequential diffusion-controlled mineral growth mechanisms. The individual corona–symplectite layers consist of clinopyroxene + quartz|garnet + clinopyroxene|garnet + quartz|K-feldspar, from the inner to the outer margins of the coronae. The single-value decomposition models suggest that the multilayered coronae were formed in a locally closed system, via sequential diffusion of Mg, Fe and Ca into the reaction zone, which has acted as the main driving force for the growth of corona textures. The relict orthopyroxene with exsolved clinopyroxene yields primary crystallization conditions of 8.4 ± 1.5 kbar and ~ 1100–1000 °C. Clinopyroxene in the innermost corona layer grew at ~ 9 kbar and 850–800 °C, whereas clinopyroxene + garnet grew outward at ~ 8 kbar and 700–600 °C. Subsequent hydrous retrogression (~ 6 kbar and 600–550 °C) resulted in the development of rimward zoning in garnet and the growth of amphibole. On combining textural relations and the above conventional P–T estimates, a near-isobaric cooling P–T path was reconstructed using phase equilibria modeling. Further, the near-isobaric cooling path is consistent with the magmatic underplating hypothesis in the Sandmata Complex, where the intrusion of magmatic bodies (i.e., Gyangarh–Asind igneous complex and Anjana granite) favored the development of granulite facies assemblage in norite and gabbronorite protoliths.

Metal-Nitride nanocomposite thin film of nanomaze-like Cu embedded in TiN

Nanocomposite thin film has attracted tremendous research interests, owing to its great potential to achieve multifunctionality, property enhancement and tuning, as well as new physical phenomenon exploration. In this work, a new nanocomposite thin film of Cu-TiN has been designed and fabricated by pulsed laser deposition (PLD) method. The metal-nitride film exhibits interesting structure of nanomaze-like Cu nanostructure embedding into TiN matrix without apparent inter-diffusion between Cu and TiN. Such Cu-TiN nanocomposite thin film shows excellent crystallinity and highly textured growth for both Cu and TiN phases. Furthermore, interesting optical properties are obtained, for example, the real part (ε′) of the complex dielectric permittivity starts to show negative value from the wavelength of ∽450 nm, compared to the pure TiN film of ∽500 nm. In addition, strong localized surface plasmon resonance (LSPR) is observed at ∽400 nm for the Cu-TiN film, which suggests its great potential for optical device applications.

AB-stacked nanosheet-based hexagonal boron nitride.

Hexagonal boron nitride (h-BN) has been generally interpreted as having an AA stacking sequence. Evidence is presented in this article indicating that typical commercial h-BN platelets (∼10-500 nm in thickness) exhibit stacks of parallel nanosheets (∼10 nm in thickness) predominantly in the AB sequence. The AB-stacked nanosheet occurs as a metastable phase of h-BN resulting from the preferred texture and lateral growth of armchair (110) planes. It appears as an independent nanosheet or unit for h-BN platelets. The analysis is supported by simulation of thin AB films (2-20 layers), which explains the unique X-ray diffraction pattern of h-BN. With this analysis and the role of pressure in commercial high-pressure high-temperature sintering (driving nucleation and parallelizing the in-plane crystalline growth of the nuclei), a growth mechanism is proposed for 2D h-BN (on a substrate) as `substrate-induced 2D growth', where the substrate plays the role of pressure.

Growth of Grains in the Third Orientation in an Inhomogeneous Matrix Consisting of Two Orientation Groups - A Modified Potts–Monte Carlo Simulation

The growth of a C-grain embedded in the matrix of A-and B-grains has been simulated. A, B, and C denote orientation groups. Boundaries were defined as “specified” if they consisted of A and C grains, else they were defined as “unspecified”. The edges of an embedded grain were named according to component grains as CAA, CAB, and CBB triple lines. The inhomogeneity of the matrix structure was presented as the ratio between their numbers. When the mobility of specified boundary is higher than that of unspecified boundary, the volume fraction of the C-grain increases with grain coarsening, which is affected by the ratio between triple lines. The results suggest that the development of the grain growth texture is affected by the orientation distribution in a specimen and that the influence must be bigger when the mobility of the triple line depends on the combination of relevant grains.

Preparation and properties of YBCO/Bi-2212/YBCO superconducting trilayer films by acetate based sol–gel method

YBa2Cu3O7−δ(YBCO)/Bi2Sr2CaCu2O8+δ(Bi-2212)/YBCO trilayer films with c-axis epitaxial orientation have been successfully prepared on LaAlO3 (LAO) monocrystalline substrates by sol–gel method using metallic acetates as starting materials. The effect of heat treatment temperature of upper YBCO films on the structure and superconductivity of YBCO/Bi-2212/YBCO planar-type junction have been studied. When the upper YBCO film fabricated at 750 °C, YBCO/Bi-2212/YBCO trilayer films exhibited good in-plane and out-of-plane growth texture and good superconductivity. Two superconducting transition steps in the R–T curves of YBCO/Bi-2212/YBCO trilayer films were clearly observed. Current–voltage (I–V) curves at 50–65 K of trilayer structure exhibit a supercurrent with zero voltage, and the superconducting critical current Ic is proportion to (1 − T⁄Tc)3.5. We suggest that a weak-link contact, which appears to have an SNSNS type structure, formed at the interface of YBCO/Bi-2212/YBCO trilayer structure.

Self-assembly nuclei with a preferred orientation at the extended hydrophobic surface toward textured growth of ZnO nanorods in aqueous chemical bath deposition

Textured growth of ZnO nanorods with no restriction of the substrate material is beneficial to their applications. The approaches to grow ZnO nanorods with texture are based on preparing suitable surface structure on the growth substrate, e.g. using a crystalline substrate with a specific surface structures or pre-depositing seed layers by high-temperature annealing of precursors. In the aqueous nutrient solution of the chemical bath deposition (CBD) process for ZnO growth, the concentration of Zn2+ ions at the extended hydrophobic surface is sufficiently high for forming self-assembly nuclei with a preferred orientation, resulting in the subsequent textured growth of ZnO nanorods. In this research, the hydrophobic surface is prepared by modifying Si surface with a self-assembly octadecyltrimethoxysilane (OTMS) monolayer. The formation mechanism of the nuclei on this hydrophobic surface for the textured growth of ZnO nanorods is investigated. It is shown that the nuclei form at the beginning of the CBD process and later transform into the Wurtzite structure to seed ZnO growth. An alternative approach to prepare seed layers is therefore involved in the aqueous CBD process, which is applicable to a range of hydrophobic substrates for textured growth of ZnO nanorods.

Combining zircon texture, REE patterns and U-Pb-Hf isotopes to decipher the formation process of orbicular rocks: A case study from Huangling orbicular granodiorite, Yangtze craton, China

The petrogenesis of orbicular rocks is still enigmatic because of the unique texture and variable compositions. In this study, we focus on the textural characteristics and mineral compositions from Huangling Orbicular Granodiorite (HOG), where orbicules with rhythmic growth texture and radial growth texture exist in the same outcrop. Textural and isotopic studies of zircons from different parts of the representative orbicules show three age groups of 1961 ± 19 Ma, 890 ± 6 Ma and 852 ± 6 Ma, corresponding to the ages of protolith crystallization, melt emplacement, and input of a new magma, respectively. Combined with field relationship, Ti-zircon crystallization temperature, trace element modelling and Hf isotopic data, the HOG may be derived from high-temperature contact process that involved the partial melting of granodiorites in contact and interaction with a quartz-bearing dioritic intrusion.Textural features and mineral compositions of the studied orbicules show that different textures are related to different states of crystallization. Orbicules with a rhythmic growth texture have disequilibrium crystallization zone with feldspar An contents of 34–46 and a “W”-shape pattern (forming rhythmic layers), and near-equilibrium crystallization zone with An contents of 42–44 (forming the inner part). Orbicules with a radial growth texture was crystallization in disequilibrium, as An contents show approximate linear variations of 32–44 to form radial growth layer, and with An varies 26–46 to form the inner part.Our observations support the magma quenching hypothesis, proposed as hot orbicule melts underwent rapid cooling with inward crystallization. Moreover, we firstly suggest that the amphibole-plagioclase disequilibrium crystallization could explain different textures of orbicules. Rhythmic growth texture and radial growth texture are formed at undercooling state with fast and slow cooling rates, separately. The numbers of rhythmic layers are controlled by the duration of undercooling state, while the width of each layer is controlled by the cooling rate. If excess amphibole components left in the center of orbicule melt, the “core” will be mafic. Otherwise, the “core” will be felsic.

High In-Plane Seebeck Coefficients of Bi–Sb–Te Alloy Thin Films with Growth Texture and Their Field-Controlled Seebeck Coefficients

Bismuth antimony telluride (BixSb2–xTe3, BST) is an alloy that has widely been used over the past 5 decades for excellent p-type thermoelectric (TE) materials that operate around 300 K, for example...

Morphology and pathogenicity of Rhizoctonia solani Kühn associated with potato black scurf in Nariño (Colombia)

The objective of the research was to understand the diversity of Rhizoctonia solani in potato crops in Nariño. Tubers with sclerotia were collected from farms in the municipalities of Pasto, Ipiales, Tuquerres and Ospina. In a laboratory, the strains were grouped in categories, selecting 30 for morphological and pathogenic studies. In an PDA medium, the daily mycelia growth rate (DMGR), pigmentation, texture, growth pattern (GP) and sclerotia characteristics were determined. The hyphae width and nuclei number were also evaluated. Solanum tuberosum L. Group Phureja seedlings were used in the pathogenicity test. Initially, 494 strains were obtained with diverse cultural characteristics, grouped in 15 categories, selecting two of each one for the research. Of the 30 strains, there were significant differences in the DMGR according to the Tukey test (P=0.05), 96.6% of the strains had an average of 16.6 mm day-1. 15 day-old colonies had cream, beige, brown and salmon colors. 95% of the isolates formed plush mycelium with GP concentric simple rings, complex rings, and scattered and stellate forms. Sclerotia formation began at 6 days (average), and, at 15 days, dispersed arrangement predominated, as well as a peripheral, with brown, beige and cream colors. Three isolates did not produce sclerotia. The hyphae had a mean of 9.7 μm, and the nuclei number ranged between 7.2 - 8.2, without statistical differences. Twenty-four isolates caused 100% plant infection. The results suggest differences between the isolates, associated with levels of pathogenicity or anastomosis groups (AG), characteristics that will be studied in future research.

A Preliminary Study on the Diversity of Fusarium solani, Causing Dieback Disease of Tea (Camellia sp) and its Alternate Hosts

This study deals with the diversity among isolates of Fusarium solani of different locations of Dooars tea growing areas of West Bengal and its alternate host range. This pathogen causes dieback disease of tea and adversely affects crop production to the great extent. The pathogen was isolated from diseased tender shoot samples of various locations. These isolates were further, in vitro studied to assess their cultural and morphological variability, using potato dextrose agar medium. Results revealed that isolates exhibited huge variation in mycelial growth rate, texture, color, and sporulation. They produced dull-white, off-white, light pink, and violet-colored colonies. Some isolates produced fluffy whereas others produced flat colonies in plates. KBN-7 showed the highest mycelial growth rate followed by KBF-3, 2, 9, and 1, however, isolates KBF-5, 6, 8, and 4 were found to be slow growers in plate culture. Isolates showed differences in sporulation, as well. Isolate KBF-8 and 9 produced higher numbers of conidia, whereas KBF- 1, 2, 5, and 6 produced moderate numbers of conidia. Isolate KBF-3 produced a fair number of conidia whereas isolate KBF-4 and 7 produced the least conidia and hence categorized them as poor sporulator. There was significant variation for germination of conidial among the isolates, also. To find out the alternate hosts of this pathogen, out of the seven other host plants studied, none was found to be an alternate host in support of its life cycle.

Correlation between growth texture, crystallite size, lattice strain and corrosion behavior of copper-carbon nanotube composite coatings

This study illustrates the correlation between corrosion properties, preferred growth orientation, crystallite size, size distribution, and lattice strain in electrodeposited Cu and Cu‑carbon nanotubes (CNT) composite coatings with different CNT additions. Cu-CNT composite coatings were electrodeposited over mild steel substrate by dispersing different CNTs into the electrolyte bath. Lower CNT incorporation enhanced the coating compactness and produced finer coating morphology. In contrast, higher CNT amounts produced rougher and defective coating morphology primarily due to the agglomeration of CNTs. The crystallite size, size distribution, preferred growth orientation, and strain in the coatings were sensitive to the CNT amount. With increasing CNT addition, growth along (111) planes was preferred. With continued CNT addition, crystallite size, size distribution, and lattice strain initially decreased to the lowest value, and then it increased at higher CNT additions. A similar trend of initial decrease followed by increase was also observed for the coatings' corrosion rate with continued CNT addition. The optimum CNT amount produced the lowest corrosion rate also yielded maximum growth along the low energy (111) planes, smallest crystallite size, lowest size distribution and lowest lattice strain.

Effect of manganese sulfate and vitamin B12 on the properties of physicochemical, textural, sensory and bacterial growth of set yogurt

In this study, the effect of MnSO4·H2O (Mn2+) and vitamin B12 (VitB) on the physicochemical, textural, sensory properties, and bacterial growth of set yogurt were evaluated. A commercial culture containing Lactobacillus bulgaricus delbrueckii and Streptococcus thermophilus and the probiotic bacteria Lactobacillus acidophilus LA5 were used for yogurt production. Moreover, individual and combination treatments of Mn2+ at concentration of 0.006, 0.03, and 0.3 w/w and VitB 0.05, 0.1, and 0.5 w/w were used in the product. Changes in bacterial count of yogurt culture, probiotic bacteria, pH, amount of lactic acid production, hardness, syneresis, color, and sensory properties were examined duration incubation until a pH level of 4.6 at 37 °C. Results showed that the addition of Mn2+ and VitB had a significant beneficial effect on the incubation period time. The most significant decreases in incubation period were obtained at 0.006 Mn2+ + 0.5 VitB, 0.03 Mn2+, and 0.5 VitB % which were reduced the incubation time from 300 min to 165, 210, and 225 min, respectively. Combined treatments of Mn2+ and VitB were able to increase the growth of Lactobacillus bulgaricus delbrueckii by 23.6% compared to the control. However, the fermentation process became significantly slower than the control sample when treatments of 0.006 Mn2+ %, 0.3 Mn2+ %, 0.05 VitB %, and 0.1 VitB % were applied. Best results for textural, sensory, and color properties were observed in samples produced by 0.006 Mn2+ + 0.5 VitB. The results showed that the addition of ions and vitamins in milk to reduce the incubation time was directly related to their concentration and their synergistic effects, and therefore their critical levels must be carefully taken into account.

Evidence of Rapid Phenocryst Growth of Olivine During Ascent in Basalts From the Big Pine Volcanic Field: Application of Olivine‐Melt Thermometry and Hygrometry at the Liquidus

AbstractThe Quaternary Big Pine (BP) volcanic field in eastern California is notable for the occurrence of mantle xenoliths in several flows. This points to rapid ascent of basalt through the crust and precludes prolonged storage in a crustal reservoir. In this study, the hypothesis of phenocryst growth during ascent is tested for several basalts (13–7 wt% MgO) and shown to be viable. Phenocrysts of olivine and clinopyroxene frequently display diffusion‐limited growth textures, and clinopyroxene compositions are consistent with polybaric crystallization. When the most Mg‐rich olivine in each sample is paired with the whole‐rock composition, resulting (olivine‐melt) values (0.31–0.36) match those calculated from literature models (0.32–0.36). Application of a Mg‐ and a Ni‐based olivine‐melt thermometer from the literature, both calibrated on the same experimental data set, leads to two sets of temperatures that vary linearly with whole‐rock MgO wt%. Because the Ni thermometer is independent of water content, it provides the actual temperature at the onset of olivine crystallization (1247–1097°C), whereas the Mg thermometer gives the temperature under anhydrous conditions and thus allows ΔT (=TMg − TNi = depression of liquidus due to water) to be obtained. The average ΔT for all samples is ~59°C, which is consistent with analyzed water contents of 1.5–3.0 wt% in olivine‐hosted melt inclusions from the literature. Because the application of olivine‐melt thermometry/hygrometry at the liquidus only requires microprobe analyses of olivine combined with whole‐rock compositions, it can be used to obtain large global data sets of the temperature and water contents of basalts from different tectonic settings.

Texture tolerance to B-site valence mismatch for [001] textured Pb97.5%Ba2.5%[(Zn1/3Nb2/3) (1-x)–Tix]O3 transparent ceramics

Transparent Pb97.5%Ba2.5% [(Zn1/3Nb2/3) (1-x)–Tix]O3 ceramics have been textured using BaTiO3 template. The influence of B-site valence mismatch between the host and the template on texture growth is investigated. The texture degree depends on the Ti4+ content in the host. The minimum Ti4+ content of 9% is necessary for texture growth. X composition in the vicinity of 9% is demonstrated at MPB where the maximum d33 and kp is 660 pC/N and 63%, and a strain as high as 0.27% at 40 kV/cm is achieved. The transmittance of textured P97.5%B2.5% (ZN–4%T) ceramic is 47% at 600 nm and exceeds 60% at the wave length of 1000–3000 nm. This research gives a better understanding of texture growth and facilitates the designs of multi-functional devices.

Effect of varying N2 pressure on DC arc plasma properties and microstructure of TiAlN coatings

Detailed knowledge of correlations between direct current (DC) cathodic arc deposition process parameters, plasma properties, and the microstructure of deposited coatings are essential for a comprehensive understanding of the DC cathodic arc deposition process. In this study we have probed the plasma, generated by DC arc on a Ti-50 at.% Al cathode in a N2 ambience, at the growth front of the TiAlN coating. Several consequences of an increasing N2 pressure are observed, including a decreased electron temperature, an increased electron density, and a loss of energetic ions. As a result, the preferred growth texture switches from 220 to 111. It is also observed that neutrals in the plasma can significantly contribute to the growth of TiAlN coatings.

Enhancement in the corrosion resistance of nanocrystalline aluminium coatings by incorporation of graphene oxide

Non-aqueous electrolyte containing aluminium chloride (AlCl3) and 1-ethyl-3-methylimidazolium chloride ([EMIm]Cl) topped with n-decane was used to electrodeposit aluminium (Al) coating via chronoamperometric method at ambient atmosphere. Aluminium-graphene oxide (Al-GO) composite coating was further obtained from the Al electrolytic bath by dispersing GO in it. GO was prepared by oxidation of high purity graphite. The Al deposition potential was noted by cyclic voltammetry (CV) method. Influence of GO on the morphology and microstructure of Al metal matrix was analysed by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction spectroscopy (XRD). Inclusion of GO into the Al matrix enhanced the coating compactness thus nullifying the surface defects which were observed for the pristine Al deposit. The texture co-efficient calculation showed that the addition of GO altered the growth texture from growth predominately along (002) plane for pure Al coating to growth predominantly along (111) and (022) plane for Al-GO composite coating. The morphological and microstructural changes occurred in the Al coating from GO incorporation influenced the anti-corrosion behaviour of the coatings. The electrochemical corrosion analysis by Tafel polarization and Impedance Spectroscopy confirmed that the GO reinforced Al deposit possessed two-fold enhanced anticorrosive property than pure Al coating.

BaFe &lt;sub&gt;12&lt;/sub&gt;O &lt;sub&gt;19&lt;/sub&gt; Magnetoplumbite Films Grown on Sio &lt;sub&gt;2&lt;/sub&gt;/Si Substrates for Widescale Magnetic Film Semiconductor Systems Integration

Barium hexaferrite (i.e., BaFe12O19) finds application in magnetic memory and radio frequency devices. Here, we report highly textured BaFe12O19 magnetoplumbite thin film growth by pulsed laser deposition directly on amorphous thermal oxide wafers (i.e., SiO2/Si) opening an avenue for the monolithic integration of ferrites onto silicon-based platforms compatible with semiconductor systems and processing. The films and, in particular, their interfaces have been characterized by vibration sample magnetometery, scanning and transmission electron microscopy, and energy dispersive x-ray spectroscopy. In the past, comparable hexaferrite films have been grown only on crystalline substrates with well-matched lattice parameters, e.g., sapphire or magnesium oxide.

BaFe12O19 magnetoplumbite films grown on SiO2/Si substrates for widescale magnetic film semiconductor systems integration

Barium hexaferrite (i.e., BaFe12O19) finds application in magnetic memory and radio frequency devices. Here, we report highly textured BaFe12O19 magnetoplumbite thin film growth by pulsed laser deposition directly on amorphous thermal oxide wafers (i.e., SiO2/Si) opening an avenue for the monolithic integration of ferrites onto silicon-based platforms compatible with semiconductor systems and processing. The films and, in particular, their interfaces have been characterized by vibration sample magnetometery, scanning and transmission electron microscopy, and energy dispersive x-ray spectroscopy. In the past, comparable hexaferrite films have been grown only on crystalline substrates with well-matched lattice parameters, e.g., sapphire or magnesium oxide.