Increase Of Annealing Temperature Research Articles

Effect of high temperature annealing on microstructure and mechanical properties of Morlion735 alumina fiber

Continuous alumina fiber-reinforced alumina (Al2O3/Al2O3) composite is a very promising candidate for thermal structural materials in aerospace vehicles and other applications. Alumina fibers used in Al2O3/Al2O3 composites play a crucial role in enhancing their mechanical properties and thermostability. In this article, the effect of annealing on the tensile strength and microstructure of Morlion735 alumina fiber was investigated. The results showed that the phase transformation occurs at 1147 °C, resulting in a mullite phase with an orthogonal lattice structure. As the annealing temperature increases, the crystal domain size of the mullite gradually increases. Both the phase transformation and the increasing crystal domain size lead to more lattice defects, which significantly affect the tensile strength and tensile modulus of alumina fibers. A 0.67 GPa reduction in tensile strength (from 1.14 GPa to 0.47 GPa) was observed when the annealing temperature increased from 1200 °C to 1400 °C. Weibull statistical analysis revealed that as the annealing temperature increased, the tensile strength dispersion of Morlion735 fiber also increased. This can be attributed to the volume-dependent flaw distributions. These results provide an in-depth understanding of the tensile strength evolution mechanism under high temperatures.

Effect of annealing temperature on the evolution of microstructure, texture, and mechanical properties of hot-rolled 12Cr-ODS steel

To achieve high thermal efficiency, today's nuclear reactor structures are exposed to higher temperatures and pressures, which requires the use of high-strength steels with specific properties, such as ODS steels. There is a need to clarify the evolution of the microstructure and properties of steels at elevated temperatures. This study systematically investigates the evolution of microstructure, texture, and mechanical property variations of 12Cr-ODS steels after hot-rolling and subsequent annealing at 1000 °C and 1200 °C. The investigation utilizes optical microscopy, electron backscatter diffraction technique, and mechanical property measurements. The microstructure of hot-rolled samples shows a layered alternating distribution, which is distinguished by a notable presence of the α-fiber texture. Following annealing at 1000 °C, the martensite grains are smaller with a reduced hardness, while maintaining a strong α-fiber texture. After annealing at 1200 °C, there is a rapid increase in the growth of martensite grains, a significant rise in hardness, a reduction in the α-fiber texture characteristics, and an improvement in the γ-fiber texture characteristics. Moreover, the maximum intensity of the α-fiber texture diminishes as the annealing temperature increases. The mechanical properties of the samples deteriorated after annealing at 1200 °C, which can be attributed to the coarse martensite grains and the texture components containing the {001} cleavage plane dominating the occurrence of brittle cleavage fracture. The 0.1Y sample after annealing at 1000 °C exhibits an excellent combination of strength (1458 MPa) and ductility (20.3%), which is owing to the unique heterogeneous grain structure and the evolution of favorable texture.

Effect of heat treatment on the microstructure and nanoindentation behavior of AlCoCrFeNi high entropy alloy

In the present work, the effect of annealing temperature on the phase evolution, morphology, and nanoindentation behavior of the equiatomic AlCoCrFeNi high entropy alloy (HEA) were investigated, and the correlation between the microstructure and nanoindentation behavior in the dendrite core (DC) and inter-dendrite (ID) regions was revealed. The DC and ID regions in the as-cast alloy are composed of disordered A2 particles and ordered B2 matrix. As the annealing temperature increases, the volume fraction of the face centered cubic (FCC) phase first increases and then decreases, leading to complete dissolution of FCC phase at 1200 °C. In addition, annealing at 700 and 800 °C results in the precipitation of the σ phase in the ID region. DSC and thermodynamic calculations were used to analyze the phase evolution of the alloy with temperature. Changes in morphology and phase constituent inevitably affect the mechanical properties of the alloy, which were characterized by nanoindentation for both ID and DC regions. The results show that the ID region displays higher nano-hardness than the DC region in the as-cast and 600–800 °C samples, but there is no difference in the 900–1200 °C temperature range.

Influence of annealing temperature on the mechanical properties and corrosion behavior of Ti-5.5Al-2.0Zr-1.5Sn-0.5Mo-1.5Nb alloy

In this work, the effect of annealing temperature of Ti552 titanium alloy is systematically investigated based on mechanical property tests, electrochemical tests and static immersion tests. The results show that after the annealing treatment, the microstructure morphology of the α-phase transforms from striated to equiaxed, and the intergranular β-phase gradually increases. As the annealing temperature increases, the grain size gradually increases and the volume fraction of α-phase gradually decreases. The tensile strength and Vickers hardness are the maximum and the elongation is the minimum in the hot-rolled condition. With increasing annealing temperature, the strength and Vickers hardness of Ti552 alloy gradually decrease, while the elongation gradually increases. In 3.5 wt% NaCl solution, Ti552 alloy has similar corrosion behavior at different annealing temperatures, although its corrosion resistance varies. In potentiodynamic polarization and EIS testing, the annealed Ti552 alloy shows a low corrosion current density (10-6 A/cm2) and a high polarization impedance (106 Ω·cm2), indicating the formation of a dense and stable oxide film. Under annealing at 800 °C, the corrosion resistance is at its highest and the corrosion rate is the lowest, according to electrochemical and static immersion studies. The comprehensive analysis suggests that the corrosion behavior of Ti552 alloy in NaCl solution may be a result of the combined effect of the volume fraction of the β-phase and the grain size of the α-phase.

Deformation mechanisms and mechanical properties of rolled AZ31 alloy subjected to precompression and subsequent annealing: Effect of annealing temperature

This study investigates the effect of annealing temperature on the microstructure, deformation behavior, and mechanical properties of a rolled AZ31 alloy having {10–12} twins. To this end, rolled AZ31 samples are precompressed to 6.0% along the rolling direction (RD) to introduce {10–12} twins and then are annealed at 200, 250, and 300 °C for 1 h. The results reveal that as the annealing temperature increases, the grain size of the annealed samples increases and their RD-oriented basal texture is strengthened. In addition, the number of {10–12} twin boundaries gradually decreases and they almost disappear after annealing at 300 °C. Under tension along the RD, the predominant deformation mechanism of the annealed samples changes from detwinning of preexisting twins to {10–12} twinning as the annealing temperature increases. The annealed samples exhibit different tensile strengths and elongations according to the annealing temperature. Particularly, the tensile elongation increases by 56%, from 13.2% to 20.6%, as the annealing temperature increases from 200 to 300 °C. The variations in the mechanical properties of the annealed samples with the annealing temperature are discussed in detail on the basis of their microstructural characteristics and deformation behaviors.

Effect of Rapid Thermal Annealing on CuO Nanoparticles

Abstract This work is a comparative study of the effect of two different annealing methods on copper oxide (CuO) nanoparticle properties obtained previously by direct precipitation method. The prepared samples were annealed in air at various temperatures (300, 400, 500°C) for 1 hour. Then they were characterized by employing scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-Visible, and Fourier Transform Infrared (FT-IR) spectroscopy. The main results revealed an increase in the grain size in both methods as the annealing temperature increases. It reaches 30.93 nm in RTA and 26.75 nm in STA at 500°C. XRD spectra showed, in the case of RTA at 500 °C, a significant decrease in the intensity corresponding to the (002) and (111) orientations. This result indicated that beyond 400 °C, one hour of RTA is not suitable for enhancing CuO nanoparticle crystallinity compared to STA. The optical analysis demonstrated that the energy of the optical band gap in STA is higher than that in RTA. It reaches 2,88 eV at 500°C using RTA which is close to the gap value of CuO in the range of 1.8–2.8 eV. FT-IR results showed, for both methods, the presence of characteristic peaks of the Cu-O bonds in the monoclinic CuO structure without any trace of Cu2O structure. Nevertheless, samples exposed to RTA for one hour are more susceptible to absorbing species of C=O bond (C=O bond is due to the atmospheric CO2 absorption and the presence of organic impurities from the synthesis process) than those of STA. Hence, RTA at 500 °C is far from producing CuO nanoparticles with preferred characteristics; it needs further research to examine the effect of higher temperature by controlling the annealing time.

Synthesis, negative thermal expansion and optical performances of In0.5Sc1.5Mo3O12 thin films via sol-gel spin coating

Orthorhombic In0.5Sc1.5Mo3O12 thin films have been synthesized using the sol-gel spin coating. Influences of post-annealing temperatures on crystal structure, morphology, negative thermal expansion (NTE) and optical performances of the thin films were studied using XRD, SEM, XPS, high-temperature XRD and UV–Vis–NIR spectrophotometer. XRD and SEM results show that as-prepared thin film is in an amorphous state with a smooth and dense surface. Orthorhombic In0.5Sc1.5Mo3O12 thin films were obtained after post-annealing in 550–750 °C. The higher the annealing temperature in 550–750 °C, the better the crystallinity of orthorhombic In0.5Sc1.5Mo3O12 thin films. In addition, the grain size of the In0.5Sc1.5Mo3O12 thin film also grows as the annealing temperature increases. The resulting orthorhombic In0.5Sc1.5Mo3O12 thin films exhibit anisotropic NTE. Its volumetric coefficient of thermal expansion (CTE) is −3.44 × 10−6 °C−1, while the CTEs in a-, b- and c-axis directions are −4.70 × 10−6 °C−1, 5.37 × 10−6 °C−1, and -4.10 × 10−6 °C−1 in 25–700 °C, respectively. In addition, the transmittance of orthorhombic In0.5Sc1.5Mo3O12 thin films post-annealed at 750 °C is around 87.75 %–95.03 %.

Evolution of Microstructure, Properties, and Fracture Behavior with Annealing Temperature in Complex Phase Steel with High Formability

In recent years, with the continuous improvement in the requirements for automobile steel formability, complex phase steel with high formability (CH steel) has been widely used. In the present study, the microstructure of CH steel was regulated using the actual production process as a basis and annealing temperature as a variable, and the effects of annealing temperature on the microstructure, properties, and fracture behavior of CH steel were analyzed. As the annealing temperature increases, the ferrite content decreases from 36.3% to 0, the martensite content decreases from 49.3% to 8.8%, the bainite content increases from 11.9% to 87.1%, and the retained austenite content first increases and then decreases within the range of 2.5~5.1%. Consequently, the tensile strength shows a decreasing trend, the yield strength first decreases and then increases, and the total elongation and the hole expansion ratio first increase and then decrease. The deformation coordination of each phase gradually becomes better, and the voids and cracks in the tensile and hole expansion samples expand along the ferrite and martensite or martensite/austenite (M/A) island interface, transforming into the bainitic ferrite and martensite or M/A islands. The test steel’s best tensile and hole expansion properties occur at annealing temperatures of 940 °C.

Negative bias stress stable PtOx/InGaZnOx Schottky barrier diodes optimized by oxygen annealing

In this work, bottom-Schottky-structure InGaZnOx (IGZO) Schottky barrier diodes (SBDs) with sputtered PtOx anodes were fabricated and annealed in oxygen at different temperatures. Critical parameters and negative bias stress (NBS) stability of SBDs with different annealing temperatures are investigated. With the annealing temperature increases, the barrier height and rectification ratio of the SBDs exhibited a rising-then-declining trend, while the ideality factor slightly increased until 200 °C. The SBDs show up overall reliability except for a leakage current rising trend under light, which can be attributed to free electron generation from the ionized oxygen vacancy. Among all the SBDs, the 175 °C annealed ones exhibited the best overall performance, including a high barrier height of 0.89 eV, an ideality factor of 1.14, and a large rectification ratio of over 108. Compared to the initial SBDs, the annealed ones showed up great improvement in NBS stability except for the 200 °C annealed ones, which was permanently degraded and not able to recover to original states. According to experimental result analysis and IGZO material characteristics, a stability model based on the subgap trap transition from VO2+ to VO and new VO2+ creation was proposed, which applies to both the short-term and long-term NBS tests. The results above demonstrate that oxygen annealing at appropriate temperature is an effective method to improve both device performance and NBS stability for PtOx–IGZO SBDs.

INVESTIGATION THE IMPACT OF DIFFERENT ANNEALING TEMPERATURES ON STRUCTURAL AND OPTICAL PROPERTIES OF BI-DOPED GETE (BI: 5 %) THIN FILMS FABRICATED BY PVD TECHNIQUE)

The impact of different annealing temperatures on the Bi-doped GeTe thin films were investigated. The thin films have been prepared by using physical vapor deposition techniques (PVD). The Bismuth (Bi) is doped GeTe with ratio of 5%. Different characterizations techniques have been used to study the different properties of thin films with several annealing temperatures. It has been found that the film thickness decreases as the annealing temperature increases. The XRD patterns show that as-deposited and annealed Bi-doped GeTe films at 150°C,200°C, and 250°C were fully amorphous, while the film annealed at 100 °C was crystalline. FESEM image shows that the structure is amorphous with no grain appearing for the crystallite GeTe compound. Whereas the annealed thin films at 100°C are well-appeared crystallites of GeTe with an average size of (110.64 nm). The thin films are annealed at (150, 200, and 250)°C which reveals that the crystallite or grain is increased. An increase in the annealing temperature has been found to cause a significant shift in the absorption edge toward an extended wavelength and an overall reduction in transmittance. At a wavelength of 1100 nm, the transmittance dropped from 65.25% for as-deposited thin films to 32.57% for annealed thin films at 250 °C. Furthermore, when the annealing temperature rises from 100°C to 250°C, the optical band gap reduces from 0.95 eV to 0.42 eV.

Underlying mechanism of interfacial evolution in laminate IN625/TC4 composites for enhanced mechanical properties

Compared to the homogeneous materials, laminated heterogeneous materials, in contrast to their homogeneous counterparts, display enhanced performance by effectively balancingcombination of strength and plasticity. However, fabricating such materials is challenging, relying on precise interfacial control. In this work, an IN625/TC4 layered structural material is successfully fabricated by vacuum diffusion bonding process at 900 °C. The IN625/TC4 composite exhibits good combination of strength and ductility due to its layered hetero-structure, is due to mechanical incompatibility between different layers. The diffusion layer's Ni and Ti gradient distribution leads to distinct intermetallic compounds formation, including Ti2Ni, Ni3Ti precipitates, and disordered TiNi entities at the interface. Diffusion-driven interfacial reactions suggest interconnected growth mechanisms of individual intermetallic compounds. Post-bonding annealing treatments reinforced the composite, with annealing temperature affecting tensile strength and ductility. Increased annealing temperature effectively enhanced strength, peaking at 800 °C (857 MPa), but reduced ductility due to additional intermetallic compounds. This study presents a novel structural design for metallic materials to obtain good combination of strength and ductility.

Investigation of thermal stress effects during annealing of hafnia-made thin film using molecular dynamics simulations

Hafnia or hafnium oxide is a high-κ dielectric material with paramount importance in the realm of semiconductor devices. Recent advancements in 3D device structures require a few nanometer-thick conformal films on non-planar substrates. During the fabrication stage, the annealing process of thin films has been discovered to mitigate delamination issues at the film-substrate interface. However, it has been observed that the residual stress, which emerges as the film cools to room temperature, may lead to delamination. In this study, we propose an idealized atomistic model to mimic the critical region of a 3D-NAND structure, to get insights into the effect of thermal stress and delamination during the annealing of hafnia-made thin film. We employ molecular dynamics simulation using charge-optimized many-body potential (COMB) to perform heating and cooling simulations for different thicknesses of the hafnia layer. Our results suggest that, during heating, as the annealing temperature increases, the severity of delamination decreases. At extremely low thickness of the hafnia layer, delamination does not occur. However, significant delamination is observed during the cooling process, especially when the high temperature gradient is high.

The differences in phase transition characteristics of antiferroelectric PbZrO3 thin films via grain size engineering

PbZrO3 (PZO) possesses a unique antiferroelectric-ferroelectric (AFE-FE) phase transition under an external electric field and engages more attention in understanding and regulating the phase transition behavior. In this work, changing annealing temperature (600–750 °C) and ultralow content (5‰) ions doping are used to optimize the phase transition of PZO films via grain size engineering. As annealing temperature increases, the maximum polarization Pmax increases but forward/backward switching fields EF/EA reduce accompanied by the average grain size enhances from 622 to 686 nm. Following, 5‰ mol aliovalent ion La3+ or K+ doped PZO-650 films both enhance Pmax and EF/EA indicating the strengthened antiferroelectricity, and meanwhile the grain size enhances to ∼800 nm. A high discharge density of 31 J/cm3 is achieved for 5‰ mol La-doped PZO films at a low electric field of 1 MV/cm, which is ∼100 % higher than those of pure PZO films at different annealing temperatures. This work compares the phase transition characteristics changes in PZO films by changing annealing temperature and ultra-low content ion doping strategy, which would provide new thinking in grain size-engineered antiferroelectric materials for energy storage applications.

Photocatalytic activity of ZnO-Zn nanoparticles after nanosilver covering and annealing

The research evaluated the photocatalytic activity (PCA) of zinc oxide nanoparticles (NPs) produced by pulsed electron beam evaporation (PEBE). The ability of NPs to accelerate the photodegradation of methyl violet dye under UV exposure was considered. The paper presents an analysis of changes in catalytic activity after annealing and coating with nanosilver of the studied samples. It has been shown that as the annealing temperature increases, the PCA increases, especially for doped particles. The highest catalytic ability was shown by doped NPs ZnO-Zn+Ag annealed at a temperature of 400 °C. This sample allowed to increase the photodegradation of the organic dye by more than 6.5 times compared to the control.

Decreasing of Magnetic Saturation of Yttrium Doped Cobalt Ferrite Prepared by the Sol-Gel Auto-Combustion

In this research, a nano-sized cobalt ferrite material doped with Yttrium has been successfully fabricated using the sol-gel method of automatic combustion with variations in low sintering temperatures of 200, 300 and 400 °C. The results of refinement of XRD data using the Rietveld method show that the Yttrium-doped cobalt ferrite compound with a Yttrium concentration molarity of 0.1 possess a cubic crystal system and Fd-3m space group. The increasing annealing temperatures also increase the crystallite size of Yttrium-doped cobalt ferrite with the highest magnitude of 16.05 nm. The FTIR results of the samples indicated the presence of Co-O bonds around wave number 385 cm−1 and Fe-O bonds around wave number 582 cm−1 which are characteristic of the presence of cobalt ferrite compounds. From the VSM measurement results, it can be seen that there is a decrease in magnetic saturation with an increase in annealing temperature. The presence of Yttrium substitution, which takes the place of Fe3+ in cobalt ferrite material, indicates lower saturation magnetization. Image from SEM results showed samples have nanoparticle crystallite size. Evaluation of potential photocatalyst applications using a UV-Visible Spectrophotometer (UV-Vis). For Yttrium doped cobalt ferrite at 200 °C, the best degradation efficiency of Congo Red findings showed a magnitude of 76.10 %; the results are confirmed by the occurrence of the smallest crystallite size (15.11 nm). HIGHLIGHTS Preparation of yttrium-doped cobalt ferrite by the sol-gel auto-combustion method with various annealing temperatures The presence of Yttrium substitution, which takes the place of Fe3+ in cobalt ferrite material, indicates lower saturation magnetization Yttrium-doped cobalt is applied for photocatalytic Congo Red dye in water with the best performance according to the smallest crystallite size GRAPHICAL ABSTRACT

Zinc sulfide thin films deposited by chemical bath: Tuning consideration of structural, optical band gap, and electrical properties for CIGS solar cells application

Zinc sulfide (ZnS) is widely employed in a solar cell structure as a buffer layer due to its excellent physical and chemical properties. ZnS elements discovered in the earth's crust are safe. This study examined the performance characteristics of ZnS thin films deposited on soda lime glass substrate via chemical bath deposition. The ZnS thin films were annealed at temperatures of 300, 400, and 500 °C in a vacuum environment. XRD showed the ZnS thin films with high annealing temperatures are composed of a wurtzite structure. Increased annealing temperature improved crystallization, average crystallite sizes, film thickness, and low dislocation density as well as lattice strain. The FESEM analysis reveals that the morphology of annealed thin film at high temperatures has larger grains compared to the deposited films. EDS spectra confirm that zinc and sulfur are present in the ZnS thin film. Annealed films have an average transmission of 20–50 % in the visible spectrum of 300–1100 nm. Films exhibit 103 Ωcm resistivity, and the bulk carrier density ranges between 1012 and 1014 cm−3. The annealed film at 500 °C has a direct band gap of 3.47 eV, a resistivity of 1.79 × 103 Ωcm, and a bulk concentration of 1.19 × 1014 cm−3. All ZnS thin films have n-type conductivity.

Crystallization of amorphous anodized TiO2 nanotube arrays.

Anodized TiO2 nanotube arrays (TNTAs) prepared by anodization have garnered widespread attention due to their unique structure and properties. In this study, we prepared TNTAs of varying lengths by controlling the anodization time. Among them, the nanotubes anodized for 2 h have an inner diameter of approximately 92 nm and a wall thickness of approximately 12 nm. Then we subjected amorphous TNTAs prepared by the anodization method to annealing treatments, systematically analyzing the evolution of morphology and structure with varying annealing temperatures. As the annealing temperature increases, the amorphous successively undergoes transitions to the anatase phase and then to the rutile phase. During the transition to the anatase phase, the structure of the nanotube array remains intact, with the complete preservation of the tubular array structure. However, during the transition to the rutile phase, the tubular array structure is destroyed. To address why the tubular array remains undamaged during the amorphous-to-anatase transition, we subjected amorphous TNTAs to annealing at 300 °C for different durations. Raman spectroscopy was employed for fit analysis, providing insights into the evolution of the molecular structure during the anatase phase transition. Finally, TNTAs annealed at different temperatures were incorporated into lithium-ion batteries. By combining XRD for semi-quantitative phase content and anatase particle size calculations, we established a correlation between structure and electrochemical performance. The results indicate a significant improvement in electrochemical performance for an amorphous-anatase structure obtained through annealing at 300 °C, providing insights for the design of high-performance energy storage materials.

The microstructure and electrical and optical properties of Ge–Cu–Te phase-change thin films

The grain orientation of Ge–Cu–Te films evolves from the {111} texture with favorable carrier mobility into a random distribution with improved optical reflectivity as the annealing temperature increases.

Effect of annealing conditions on the luminescence properties and thermometric performance of Sr3Al2O5Cl2:Eu2+ and SrAl2O4:Eu2+ phosphors.

We report on the synthesis, photoluminescence optimization and thermometric properties of Sr3Al2O5Cl2:Eu2+ and SrAl2O4:Eu2+ phosphor powders. The photoluminescence of Sr2.9Al2O5Cl2:0.1Eu2+ phosphors exhibits a blue-shift with an increasing annealing temperature owing to a decrease in the crystal field strength of the host caused by evaporation of Cl from the material. The quenching of the blue band in favour of the red band observed in the luminescence spectra of Sr2.9Al2O5Cl2:0.1Eu2+ with an increased annealing temperature was explained using the mechanism of the Landau-Zener transitions. The quantum yield and the lifetime of the phosphors depend on the annealing temperature. Phosphor samples annealed at 850 °C, 1000 °C, 1200 °C and 1500 °C were found to be potential luminescence thermometers using the luminescence spectral method. For Sr3Al2O5Cl2:Eu2+ annealed at 1000 °C, the temperature-dependent dual-band intensity ratio demonstrated a high-temperature sensitivity of ∼1.47%/°C in the temperature range of 23 °C to 40 °C which is superior to other reported phosphors with a microsecond decay time, suggesting that the material has potential for sensitive thermometry applications at ambient temperatures.

INFLUENCE OF ANNEALING TEMPERATURE ON ZINC OXYSULPHIDE THIN FILMS PROPERTIES DEPOSITED BY THERMAL SPRAY TECHNIQUE

This article studies the effects of annealing temperatures on the stoichiometry, structure, and optical characteristics of Zinc Oxysulphide thin films deposited on glass substrates using the thermal spray method. The annealing was done in the air under a temperature of 150 ºC, 250 ºC and 350 ºC. Field Emission Scanning Electron Microscopy (FESEM), X-ray diffractometry (XRD), and a UV-Vis Spectrophotometer were utilized to examine the thin films' morphological, structure, and optical characteristics as grown and annealed samples. It has been observed that the film thickness decreases as the annealing temperature increases. The XRD pattern demonstrates that as-prepared and annealed samples at 250C, and 350C are amorphous, while film annealed at 150 C is crystalline with the hexagonal phase and orientated along (110) plane. FESEM image of the as-prepared Zinc Oxysulphide thin films shows flower-like sheet nanostructures. However, for the annealed samples, the FESEM images show cone-like with a combination of sheets and aggregate nanoparticles. EDX analysis reveals the presence of Zn, O as well as sulfur. The transmittance of the film decreases from 63% to 37% and the band gap energy reduces slightly from 3.99 to 3.92 eV as the annealing temperature increase.