Effect Of Heating Temperature Research Articles

Effect of Heat-treatment Temperature on Thermal and Mechanical Properties of LaMgAl11O19 Coating

Effect of Heat-treatment Temperature on Thermal and Mechanical Properties of LaMgAl₁₁O₁₉ Coating

Effects of heat treatment on the microstructure, residual stress, and mechanical properties of Co–Cr alloy fabricated by selective laser melting

The mechanical properties and residual stress of dental Co–Cr–Mo (CCM) alloy depend on the manufacturing and post-processing methods, which affect the prognosis of dental prostheses. Two CCM alloys manufactured by casting and selective laser melting (SLM) were compared, and the effect of heat treatment temperature for CCM alloys manufactured by SLM method was evaluated. Specimens were fabricated by casting (Cast Co–Cr) and SLM (SLM Co–Cr). SLM Co–Cr specimens were heat treated at 750, 950, and 1150 °C to compare their properties. Microstructures were analyzed via scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and electron backscattered diffraction (EBSD), and the residual stress was measured via x-ray diffraction (XRD). Mechanical properties were evaluated by a Vickers hardness test and a tensile test; fractography was performed after this. The SLM Co–Cr group exhibited a decrease in porosity, grain size, increase in solid solution limit, and high residual stress compared to Cast Co–Cr; the ultimate tensile strength, yield strength, and hardness were also higher. The microstructures, residual stresses, and mechanical properties differed significantly depending on the heat treatment, and the strength and hardness showed a tendency inverse to that of the elongation. Type I residual stresses mostly decreased after 750 °C heat treatment, however type II and III residual stresses remained even after 1150 °C heat treatment. SLM presented superior mechanical properties to casting. Considering the reduction of tensile residual stress and increased ductility, CCM alloys should be heat treated at a temperature of 950 °C or higher.

Effect of heat treatment temperature on microstructure and tensile properties of austenitic stainless 316L using wire and arc additive manufacturing

The effect of heat treatment temperature on the microstructure and tensile properties of 316L stainless steel fabricated by wire and arc additive manufacturing was studied in this paper. Heat treatment was used to uniformize the microstructure, eliminate the anisotropic tensile properties in as-built 316L part, and improve the poor elongation caused by the multilayered structure of alternating re-melting area (RA) and overlapping area (OA). The results showed that the heat treatments below 1000 °C had no significant effect on the multilayered structure and columnar austenite grains, but only changed the morphology and content of ferrite and σ phase within the grains. With the increase of the heat treatment temperature, ferrite transformed into σ phase and the fraction of second phase gradually decreased, leading to the slight increase of elongation but decrease of material strength and its anisotropic degree. After solution annealing above 1000 °C, the ferrite and σ phase was nearly dissolved in the austenite matrix. The austenite recrystallized and the multilayered structure was destroyed, which played a major role in the tensile properties. With the increase of heat treatment temperature, the fraction of recrystallization increased, resulting in decrease of material strength. The elongation was greatly improved and reached that of the annealed state, and its anisotropic was almost eliminated.

Effect of heat treatment on fatigue crack growth behavior of 316NG austenitic stainless steel in deaerated water at 325 °C

316NG (00Cr17Ni12Mo2N) austenitic stainless steel was heat-treated at 600, 725 and 1000 °C to investigate the effects of heat treatment temperature and holding time on the fatigue crack growth behavior of this steel in deaerated water at 325 °C. It is found that fatigue crack growth rates in air at room temperature are decreased after the heat treatments, due to a reduced dislocation density. Corrosion fatigue crack growth rates in water at 325 °C are also decreased after the heat treatments at 600 and 1000 °C for 1 h, while the heat treatment at 725 °C leads to a moderate increase in the fatigue crack growth rate. The latter phenomenon results from a higher amount of CrNbN (Z-phase) precipitates formed in the steel after the annealing at 725 °C.

Biocoke production from heat treatment of bio-oil: Effect of temperature

Coke formation becomes the major bottleneck issue to hinder the development of bio-oil upgrading technologies. Here, we propose to heat treat the bio-oil to simultaneously produce biocoke as a fuel or carbon-containing material and low coking tendency bio-oil for further upgrading. The effect of heat treatment temperature on the biocoke production from heavy bio-oil was investigated in this study. The results showed that the biocoke yield decreased rapidly from 67.14 to 12.85 wt% in the temperature range of 200–400 °C due to the quick releasing/evaporation of volatile compounds and the cracking of functionalities and heavy molecules in the biocoke. Various active functional groups in the heavy bio-oil including −OH, aliphatic C−H, CO, phenolic C−OH and C−O/C−O−C would be preferably retained in the lower temperature biocokes with high contents of O and H. Further increasing temperature from 500 to 800 °C, only a slight decrease in biocoke yield was obtained, but the polymerization/condensation of the biocoke was greatly enhanced as illustrated by FTIR and Raman results. The aromatic ring related functional groups in 500BC increased obviously, and the large aromatic ring systems in the biocoke increased with a higher C content as well. Biocoke was found to be a highly carbonaceous substance free of ash with imporous structure and very smooth surface, which can be potentially used as a high-quality fuel or further modified to value-added carbon materials.

Effect of heat treatment temperature on the microstructure and wear corrosion properties of NiCrBSi–TiN composite coatings

For this study, NiCrBSi–TiN composite coatings were fabricated on Q235 steel substrates by reactive plasma spraying and the coatings were heat treated at 600 °C, 700 °C, 750 °C and 800 °C for 1 h. The microstructure evolution of these coatings untreated and treated at different temperatures was analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) combined with energy dispersive spectroscopy (EDS) and transmission electron microscopy (TEM). The hardness of the coatings was characterised using the Weibull distribution while the wear and corrosion resistance were studied using a block-ring tribometer and an electrochemical workstation. The phase composition of coatings after heat treatment changed, the compactness of coatings was increased, and the interlayer bonding was significantly improved. Comprehensive experimental results illustrated that the performance of the NiCrBSi–TiN composite coatings was excellent at the heat treatment temperature of 700 °C.

Dielectric and microwave absorption properties of polymer‐derived TiC/SiC/SiOC multiphase ceramics in X band

AbstractPolymer‐derived TiC/SiC/SiOC ceramics were prepared using tetrabutyl titanate (TBT)‐modified polysiloxane (PSO) as precursor. The effects of heat treatment temperature and TBT content in precursor on the microstructure, phase composition, and microwave absorbing properties of TiC/SiC/SiOC ceramics were investigated. The crystallinity of the ceramics increases with the increase of heat treatment temperature. With the increase of TBT content, the TiC content of the ceramics increases and the SiC content decreases. When the TBT content ranges from 1 to 5 wt.%, the increase of TBT content has little effect on the real part of the dielectric constant of TiC/SiC/SiOC ceramics. When the TBT content is 7 wt.%, the imaginary part of the dielectric constant of the ceramics changes. For TiC/SiC/SiOC ceramic obtained from the pyrolysis of PSO‐TBT precursor with 7 wt.% TBT, the dielectric constant is within the target electromagnetic parameters. Therefore, it has an effective absorption bandwidth of 4.2 GHz, covering the entire X band, showing an excellent microwave absorbing performance.

Effect of heat-treatment temperature and zinc addition on magnetostructural and surface properties of manganese nanoferrite prepared by an ecofriendly sol–gel synthesis

ZnxMn1-xFe2O4@SiO2 nanocomposites (NCs) (x = 0.00, 0.25, 0.50, 0.75, 1.00) were prepared by eco-friendly sol–gel synthesis followed by heat treatment at different temperatures and characterized. The X-ray diffraction shows poorly crystallized ferrite after the heat treatment at low temperatures and highly crystalline ferrite accompanied by several secondary phases at high temperatures. The crystallite size increases from 2.4 to 45.2 nm with the increase of heat treatment temperature. The specific surface decreases from 281 to 13 m2/g with the increase of the heat treatment temperature, reaching values below 1 m2/g at 1200 °C. All NCs have pores within the mesoporous range, with high dispersion of pores’ sizes. The NCs show ferrimagnetic behavior, close to the superparamagentic limit. The main magnetic parameters, saturation magnetization, remanence, coercivity and magnetic anisotropy constant of ZnxMn1-xFe2O4@SiO2 nanoparticles increase with the increase of particle size and heat treatment temperature and decrease with increase of Zn content. This behavior could be explained presuming that the Zn2+, Mn2+ and Fe3+ ions can simultaneously occupy both the tetrahedral and octahedral sites in the ZnxMn1-xFe2O4 ferrite.

Heat Treatment Temperature Effect on Wettability of Laser-Machined Aluminum Surface

Heat Treatment Temperature Effect on Wettability of Laser-Machined Aluminum Surface

Wear and corrosion of Co-Cr coatings electrodeposited from a trivalent chromium solution: Effect of heat treatment temperature

Electrodeposition from a trivalent chromium bath was employed to obtain the cobalt‑chromium coatings with a thickness of ~25 μm. The effect of heat treatment temperature on characteristics, mechanical properties , and electrochemical behavior of the coatings, were examined. Heat treatment was performed in a wide range of temperatures (200–800 °C). Heat-treating below 400 °C increased the crystallinity of alloy coatings and had a negligible effect on nodular and cracked morphology. Raising the heat-treating temperature changed the X-ray diffraction patterns by thickening the surface oxide films , which consisted of different oxides (e.g., cobalt chromite spinel). The surface nodules were faded out above 700 °C. The heat-treating below 300 °C decreased the hardness and wear resistance of Co-Cr electrodeposits. The 400 °C heat-treated sample had the highest hardness of ~1000 HV, and the best tribological behavior. The weight loss and coefficient of friction of this sample were 24 and ~2 times smaller than the as-deposited coating. The hardness and wear resistance dropped again with further raising the heat-treating temperature. While detachment of coating during sliding occurred at low-temperature heat-treated samples, the abrasion was the main mechanism of material loss at those heat-treated at higher temperatures. According to the corrosion results, the optimum heat-treating temperature that the highest corrosion resistance could be achieved was 300–500 °C. The corrosion current density of 400 °C heat-treated coating was ~3.7 times smaller than the as-deposited Co-Cr film. • The relatively thick Co-Cr coatings were produced from a trivalent chromium bath. • Effect of heat treatment on Co-Cr films' characteristics and properties was studied. • Different types of oxides and morphologies were observed at various temperatures. • The 400 °C heat-treated sample showed the highest hardness and wear resistance. • Optimum heat treatment temperatures for the best corrosion resistance was 300–500 °C.

Microstructure Investigation of Thermally Induced Phase Transformation in Fe–Mn– Mo–Si Alloys

In this study, structural and crystallographic properties of phase transformations in Fe–Mn– Mo–Si (Mn = 15.14 wt.% and 18.45 wt.%) alloys were investigated. The effects of heat treatment temperature on microstructure were investigated by Scanning Electron Microscopy (SEM) and Metallurgical Microscopy (MM). In addition to this, crystallographic properties of phase transformations were revealed by using Transmission Electron Microscopy (TEM) and X–Ray Diffraction (XRD) methods. In the samples subjected to heat treatment at 750 C, it was observed that bainite structure was formed in the alloy where Mn amount was low and ferrite structure in the alloy where Mn amount was higher. In addition, it was found that both alloys heat–treated at 900 C had the same microstructure (pearlite structure) in SEM and MM microscopy. At the same time, microstructure observations revealed that bainite and pearlite structures contain a mixture of ferrite and cementite. In the TEM studies it was revealed by electron diffraction pattern analyses that bainite and ferrite phase crystallized in b.c.c. structure and cementite phase in orthorhombic structure. → type transformation was observed for –bainite formation, and orientation relationship was found as 〖(1 ̅11)〗_//〖(011)〗_ , 〖[101]〗_//〖[1 ̅11 ̅]〗_.

Effect of Heat Treatment Temperature on Microstructure and Properties of PM Borated Stainless Steel Prepared by Hot Isostatic Pressing.

Borated stainless steel (BSS) with a boron content of 1.86% was prepared by a powder metallurgy process incorporating atomization and hot isostatic pressing. After solution quenching at 900–1200 °C, the phase composition of the alloy was studied by quantitative X-ray diffraction phase analysis. The microstructure, fracture morphology, and distributions of boron, chromium, and iron in grains of the alloy were analyzed by field-emission scanning electron microscopy with secondary electron and energy-dispersive spectroscopy. After the coupons were heat treated at different temperatures ranging from 900 to 1200 °C, the strength and plasticity were tested, and the fracture surfaces were analyzed. Undergoing heat treatment at different temperatures, the phases of the alloy were austenite and Fe1.1Cr0.9B0.9 phase. Since the diffusion coefficients of Cr, Fe, and B varied at different temperatures, the distribution of elements in the alloy was not uniform. The alloy with good strength and plasticity can be obtained when the heat treatment temperature of alloy ranged from 1000 to 1150 °C while the tensile strength was about 800 MPa, with the elongation standing about 20%.

Magnesium Diffusion from MgO Substrates in Sol–Gel‐Derived NiO Epitaxial Films: Effects of Heat Treatment Temperature and Li Doping

The effects of heat treatment temperature and Li doping on the structural properties of sol–gel‐derived NiO epitaxial films on MgO (100) substrates are investigated. X‐ray diffraction measurements indicate that the out‐of‐plane lattice parameters of undoped NiO films increase as the heat treatment temperature increases. This increase is particularly significant in films treated above 900 °C, in which out‐of‐plane and in‐plane lattice parameters are larger than the expected values for bulk NiO. This result cannot be explained by the strain originating in the lattice mismatch between NiO and MgO. In addition, the bandgap drastically increases in undoped films treated above 900 °C. Secondary ion mass spectrometry depth profiling demonstrates that undoped films treated above 900 °C are Ni1−xMgxO alloys generated by the diffusion of Mg from MgO substrates into NiO films, resulting in the anomalous characteristics of the prepared films. Furthermore, it indicates that the diffusion of Mg is reduced in Li‐doped films, which can be explained on the basis of defect chemistry, in which Ni vacancies decrease with the increase in Li concentration. Consequently, the increases in the lattice parameter and bandgap at high heat treatment temperatures are reduced in Li‐doped films.

Effects of heat treatment temperatures on the photostability of Moso bamboo during accelerated UV weathering

ABSTRACT Moso bamboo were heat-treated under saturated steam atmosphere at three different temperatures separately: 120°C (low temperature heat treatment, LH group), 160°C (medium temperature heat treatment, MH group), and 195°C (high temperature heat treatment, HH group). Then, the heat-treated bamboo slivers were placed in an accelerated UV weathering tester for a total of 960 h. The samples without any treatments (C group) were also prepared for comparison. After heat treatment, bamboo showed a darker surface color and increased lignin content, especially for those treated at higher temperatures. Compared to the C group, heat-treated samples exhibited less changes in surface color, gloss, morphology, and surface chemical groups after photodegradation, suggesting improved durability after heat treatment. Among them, the HH group exhibited the best photostability during the whole weathering process. The results revealed that higher lignin content and better surface hydrophobicity of heat-treated bamboo were the main reasons for their excellent photostability against weathering.

Effect of heat treatment temperature on mechanical and tribological properties of copper impregnated carbon/carbon composite

To obtain pantograph strip with high toughness and good friction behaviors, copper impregnated carbon/carbon (C/C) composite was fabricated using chemical vapor deposition, heat treatment and impregnating technologies, and microstructure, mechanical and tribological performances were investigated. As the heat treatment temperature increases, flexural strength has a decreasing tendency, and the failure mode changes from brittle fracture to pseudo-plastic fracture. Carbon crystal degree of copper impregnated C/C composite is increased by the (Above 2000 °C) heat treatment, which helps wear surface form a smooth tribolayer, prompting the decreases of standard deviation of friction coefficient and arc discharging frequency, and the main wear mechanism changes from arc erosion to abrasive wear during the current carrying friction tests.

Nanostructured biological hydroxyapatite from Tilapia bone: A pathway to control crystallite size and crystallinity

Hydroxyapatite is the main mineral component of the bone and the main responsible for their hardness and mechanical strength. It shows enormous scientific and technological value as it presents a potential for application in medical purposes and pharmaceutical, chemical, and environmental remedy industries. Many authors have demonstrated the possibility of hydroxyapatite synthesis from different sources and synthesis methodologies. However, studies which lead to an effectively controlled crystallite size and crystallinity are still scarce. Our study aims to evaluate the effects of heat treatment temperature and high energy milling time on obtaining nanometric hydroxyapatite from a natural source. The characterization has been performed by employing thermal, chemical, structural, morphological, and surface area analysis. It has been possible to verify only hydroxyapatite formation. In the milled samples, it's been possible to verify a reduction in the crystallite size and crystallinity. The surface area increased from 0.07 to 41.37 m2/g, but excessive milling times caused agglomeration and reduced the surface area. The results showed that it is possible to synthetize nanostructured hydroxyapatite (9,8–95 nm) with crystallinity ranging from 3 to 99% from Tilapia bones. ANOVA has validated the results. The produced materials present an excellent potential for application in the biomedical or adsorption substances area.

Fabrication of LiFePO<sub>4</sub>-Based Composite Cathode Deposited on LLTO Li-Ion Conducting Solid Electrolyte via Slurry Coating and Hot-Pressing

LiFePO4 (LFPO)-based composite cathode was deposited on Li0.35La0.55TiO3 (LLTO) solid electrolyte via slurry coating method. A composite cathode comprising of LiFePO4, LLTO, and carbon black (CB) were mixed together in a slurry and deposited on a dense LLTO pellet substrate. The effects of heat treatment temperature and hot-pressing in the structure and densification of the deposited composite cathode were investigated. Cathode component precursors were analyzed for its particle size distribution using particle size analyzer and revealed a bimodal particle size distribution for each component materials. Structural characterization using X-ray powder diffraction (XRD) analysis revealed that distinct XRD peaks were observed which can be attributed to LFPO and LLTO for the deposited as-dried and heat treated (450 °C ) composite cathodes. Surface and cross-sectional SEM images revealed that hot-pressing provided denser morphology with smaller thickness as compared to the just as-dried and heat treated samples without the application of temperature with pressure.

Effect of Heat-Treatment Temperature on the Corrosion Behaviour of Cold Worked 6111 Aluminium Alloy

The present investigation studies the effects of heat treatment temperature on the corrosion behavior of cold worked 6111 aluminum alloy. The specimens were cold worked at different cold working ratios, namely, 10, 20, and 40%. They were then heat treated at 100, 200, and 400°C. Corrosion tests were performed using tap water with 0.01 M sodium hydroxide, as a corrosive medium, and the weight loss of the corroded specimens plus the corrosion rates were then calculated. Experimental results showed that corrosion rates depended on the amount of cold working percentage and the heat treatment temperature. Corroded surfaces were also photographed and analyzed. The graphs revealed large numbers of corrosion pits, in addition to crevice corrosion and fine grains of rust, and these rusts were cultivated to scales that were detached from the surfaces and were subjected to corrosive medium.

Effect of heat treatment temperature on the properties of silicon dioxide films derived from film-forming solutions

The effect of the heat treatment temperature on the physical properties of sol-gel silicon dioxide films derived from film-forming solutions is investigated experimentally. The dependencies of the thickness of the films, their refractive index, electrical strength, resistivity, etching rate, and the level of internal mechanical stresses on the treatment temperatures in the range from 700 to 1150 °C are obtained. It was found that the dependencies of the electrical strength, the etching rate, and the level of internal mechanical stresses have the sections with the different characters. The transition region between these sections corresponds to the heat treatment temperature equal to 900-950 °C.

Superior engineering critical current density obtained via hot isostatic pressing of MgB2 wires manufactured using nano-amorphous isotopic boron

The effects of heat treatment temperature, time and isostatic pressure on the grain connectivity and superconducting properties of Mg11B2 wires prepared using nano-amorphous isotopic boron powder (11B) have been investigated. The article presents detailed studies of the Mg11B2 material structure of the wires using scanning electron microscope (SEM). Heat treatment at low and high temperature for different annealing time and isostatic pressure does not create an internal macro-defect that disrupts connectivity in the Mg11B2 superconducting wires. Our study shows that dense longitudinal superconducting layers are formed at high annealing temperature of 800 °C for 60 min. Formation of dense longitudinal superconducting layers under high isostatic pressure (HIP) allow improved grain connectivity and high density of pinning centers and as a result, high engineering critical current density, Jec, at 4.2 K has been achieved. Also, high upper critical field (Bc2) and high irreversible magnetic field (Birr) were obtained using HIP process while superconducting transition temperature (Tc) was not significantly affected. Better grain connectivity obtained using high annealing temperature and long annealing time under low isotopic pressure leads to Jec enhancement at high magnetic fields at 20 K. Our results show that the annealing temperature of 800 °C for 60 min under isostatic pressure of 1 GPa yields the required Jec of 25 A/mm2 and 50 A/mm2 for ITER applications in magnetic fields of 8 T and 7 T, respectively. The promising results obtained in this work could pave the way for designing low activation superconducting Mg11B2 wires to be considered for next generation fusion magnets.