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Showing 664 results for Type of Study: Research Paper

Risa Suryana, Nida Usholihah, Markus Diantoro,
Volume 21, Issue 2 (6-2024)
Abstract

Modifying photo-anode structures in DSSC devices is still challenging in improving efficiency. This study focused on the ZnO rod growth on several porous silicon substrates using the hydrothermal method and determining which porous silicon is appropriate for DSSC applications. The materials used for the growth solution were Zn(NO3)26H2O 0.05 M and C6H12N4 0.25 M. The hydrothermal process was carried out at 90°C for 6 h and then annealed at 450°C for 30 min. SEM revealed that PSi pore influences the structure, diameter, and density of ZnO rods. ZnO structures formed in ZnO rods with a dominant vertical growth direction, ZnO rods with an intersection direction, and flower-like ZnO rods. The diameter of the PSi pore affected the density of ZnO rods grown on the PSi. The average diameter size and the density of ZnO rods vary from 747.66-1610.68 nm and 0.22-0.90 rod/μm2. XRD confirmed the presence of ZnO hexagonal wurtzite, Si cubic, and SiO2 monoclinic. UV-Vis spectrometry characterization results showed that sample reflectance was influenced by ZnO rod density and PSi pitch. The larger density of ZnO rods and the smaller pitch of the PSi pore will lead to lower reflectance. In addition, band gap values were obtained in the 3.06-3.75 eV range. FTIR identified the existence of a ZnO vibration bond, indicating that ZnO was successfully grown on all PSi substrates. The ZnO rods grown on P15S1180 are expected to have more appropriate properties among all five samples for DSSC photoanode.

Seyed Farzad Dehghaniyan, Shahriar Sharafi,
Volume 21, Issue 2 (6-2024)
Abstract

Mechanical alloying was employed to synthesize a nanostructured alloy with the chemical formula of (Fe80Ni20)1-xCrx (x= 0, 4). The microstructural and magnetic properties of the samples were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), and a vibrating sample magnetometer (VSM). Additionally, theoretical calculations were performed using density functional theory (DFT) under the generalized gradient approximation (GGA). Simulations have demonstrated that an appropriate quantity of chromium (Cr) can dissolve within the BCC-Fe (Ni) structure, resulting in a favorable enhancement of the magnetic moment of the lattice. The XRD results indicated that after 96 hours of milling, Fe (Ni) and Fe (Ni, Cr) with a body-centered cubic (BCC) structure were formed. With increasing milling time, the grain size decreased while the microstrain increased. The saturation magnetization (Ms) of Fe80Ni20 composition increased up to 32 hours of milling, but further milling (up to 96 h) resulted in a decrease in the saturation magnetization However, for the (Fe80Ni20)96Cr4 powders, milling up to 64 h caused a reduction in Ms. The coercivity (Hc) trend was different and increased with longer milling times (up to 96 h) for both compositions.
 

Lakshmiprasad Maddi, Srinivas R Gavinola, Atul Ballal,
Volume 21, Issue 2 (6-2024)
Abstract

High thermal conductivity, low coefficient of thermal expansion makes P92 a candidate material for Ultra Super Critical (USC) power plant piping. Microstructural features viz., high dislocation density, lath martensitic microstructure, fine precipitates of M23C6 and MX (X=C, N) contribute towards the high rupture strength. However, most components are typically subjected to multiaxial stress conditions; either metallurgical (weldments), or mechanical (change in the dimension). The present work involves stress rupture testing of circumferential 60° V- notch specimens in the range of 300 – 375 MPa at 650 °C. Notch strengthening effect was observed; with rupture times ranging from 200 – 1300 h. Scanning electron microscopy (SEM) fractography revealed mixed mode of fracture with brittle fracture observed at notch root, while ductile fracture was seen at the centre of the specimen.
 

Fathi Brioua, Chouaib Daoudi,
Volume 21, Issue 2 (6-2024)
Abstract

We have modeled theoretical incident photon-to-current electricity (IPCE) action spectra of poly(3-hexylthiophene) (P3HT) and [6,6]-Phenyl C61 butyric acid methyl ester active layer bulk-heterojunction. By the two-dimensional optical model of a multilayer system based on the structure of Glass substrate / SiO2 /ITO/ PEDOT: PSS /P3HT: PCBM(1:1)/Ca/Al, the optical responses of the device have been computed for different photoactive layer and Ca layer thicknesses to found an optimal structure which allows obtaining the maximum absorption localized in the active layer and high device performance. The electric field intensity, energy dissipation, generation rate, and IPCE have been computed to enhance the device's performance. The finite element method executes the simulation under an incident intensity of 100 mW/cm2 of the 1.5 AM illumination. It was found that the optimum structure is achieved by a 180 nm photoactive layer and 5 nm Ca layer thicknesses.


Rakhesh V, Sreedev P, Ananthakrishnan A,
Volume 21, Issue 2 (6-2024)
Abstract

Organic and Perovskite solar cells have attracted a lot of attention recently since they can be used with flexible substrates and have lower manufacturing costs. The configuration and materials employed in their construction, including the Electron Transport Layer (ETL), active layer, electrode contact, and hole transport layer greatly influence the stability and performance of these solar cells. This research focuses on the simulation of solar cells, specifically utilizing zinc oxide (ZnO) as the electron transport layer. A 0.1 molar ZnO thin film was prepared from Zinc acetate salt and was deposited on a glass substrate using the cost effective Successive Ionic Layer Adsorption and Reaction (SILAR) method. In-depth investigations were carried out on several factors, including structural, surface, optical and numerical analysis. The obtained parameters were utilized in the General-Purpose Photovoltaic Device Model (GPVDM) software to perform numerical simulations of the organic solar cell and Perovskite solar cell. Both Organic solar cells and Perovskite solar cells were designed numerically and through careful observations, electrical parameters like Open circuit Voltage (Voc), Short circuit current (Jsc), Fill Factor (FF), and Power Conversion Efficiency (PCE) were identified. The studies indicate the promising performance of simulated solar cells with SILAR-synthesized ZnO thin film as the ETL.
 
Padmanaban Ramasamy,
Volume 21, Issue 2 (6-2024)
Abstract

The present investigation delves into the friction stir welding of AA5052 and AZ31B alloys, examining the effects of three distinct parameter configurations. A face-centered central composite design, structured to incorporate full replications for comprehensive and reliable analysis, was employed. A pivotal element of this study is implementing an advanced deep neural network (DNN) model. Characterized by its varied activation functions, structural parameters, and training algorithms, this DNN model was adeptly configured to precisely predict the tensile strength and microhardness of the welded joints. This comprehensive examination also included a quantitative assessment of the parameter effects on joint microstructure and mechanical properties. Flawless welds with exemplary surface characteristics were attained through a meticulously optimized set of parameters: a tool rotation speed set at 825 rpm, a tool traverse speed of 15 mm/min, and a shoulder diameter of 18 mm. During the welding process, the formation of intermetallic compounds, specifically Al12Mg17 and Al3Mg2, was observed. An exceptionally refined grain size of 2.23 µm was observed in the stir zone, contributing to the joint's enhanced tensile strength, measured at 180 MPa. The hardness of the specimen fabricated at the high rotational speed is more elevated due to the brittle intermetallic compounds. The better mechanical properties are related to the reduction and distribution of intermetallic compounds formed in the interface zone.  
Alireza Zibanejad-Rad, Ali Alizadeh, Seyyed Mehdi Abbasi,
Volume 21, Issue 2 (6-2024)
Abstract

Pressureless sintering was employed at 1400 °C to synthesize Ti matrix composites (TMCs) reinforced with in-situ TiB and TiC reinforcements using TiB2 and B4C initial reinforcements. The microstructure and wear behavior of the synthesized composites were evaluated and compared and the results showed that B4C caused the formation of TiB-TiC in-situ hybrid reinforcements in the Ti matrix. Also, TiB was in the form of blades/needles and whiskers, and TiC was almost equiaxed. Moreover, the volume fraction of the in-situ formed reinforcement using B4C was much higher than that formed using TiB2. In addition, although the hardness of the B4C-synthesized composites was higher, the composite synthesized using 3 wt.% TiB2 exhibited the highest hardness (425 HV). The wear test results showed that the sample synthesized using 3 wt.% TiB2 showed the lowest wear rate at 50 N, mainly because of its higher hardness. The dominant wear mechanism in the samples synthesized using 3 wt.% B4C was abrasive and delamination at 50 N and 100 N, respectively while in the samples synthesized 3 wt.% TiB2, a combination of delamination and adhesive wear and adhesive wear was ruling, respectively.

 
Farah Zulkifli,
Volume 21, Issue 2 (6-2024)
Abstract

Researchers are increasingly focusing on green synthesis methods for silver nanoparticles due to their cost-effectiveness and reduced environmental impact. In this study, we utilized an edible bird's nest (EBN), a valuable economic resource, as the primary material for synthesizing silver nanoparticles using only water as the solvent. Metabolite profiling of the EBN extract was conducted using LC-QTOF-MS in positive mode (ESI+), revealing the presence of lipids, glycosides, peptides, polysaccharides, and disaccharides. Upon the addition of silver nitrate to the aqueous EBN extract, noticeable color changes from transparent to brown indicated the successful formation of AgNPs. Subsequent characterization of these silver nanoparticles involved UV-Visible spectroscopy, which revealed an absorption peak at 421 nm. Further characterization was carried out using FESEM, ATR-FTIR spectroscopy, and EDX analysis. The involvement of phenolic agents, proteins, and amino acids in reducing the silver particles was confirmed. The synthesized nanoparticles exhibited a spherical shape, and a particle size ranging from 10 to 20 nm. The presence of elemental silver was confirmed by a strong, intense peak around 3 keV in the EDX spectrum. To assess their potential, the antibacterial properties of the silver nanoparticles against Escherichia coli and Staphylococcus aureus were evaluated using the agar diffusion method.
 
Satish Ahire, Ashwini Bachhav, Bapu Jagdale, Thansing Pawar, Prashant Koli, Dnyaneshwar Sanap, Arun Patil,
Volume 21, Issue 2 (6-2024)
Abstract

Hybrid photocatalysts, comprising both inorganic and organic polymeric components, are the most promising photocatalysts for the degradation of organic contaminants. The nanocomposite, Titania-Polyaniline (TiO2-PANI) was synthesized using the chemical oxidative polymerization method. Various characterization techniques were employed to assess the properties of the catalysts. The ultraviolet diffuse reflectance spectroscopy (UV-DRS) analysis revealed that the TiO2 absorbs only UV light while the TiO2-PANI nanocomposite absorbs light from both UV and visible regions. The X-ray diffraction (XRD) results confirmed the presence of TiO2 (anatase) in both TiO2 nanoparticles and TiO2-PANI (Titania-Polyaniline)  nanocomposite. The phases of the catalysts were verified through Raman, TEM, and SAED techniques where all results are in good agreement with each other. The average crystallite size of TiO2 nanoparticle and TiO2-PANI nanocomposite were 13.87 and 10.76 nm. The thermal stability of the catalysts was assessed by the Thermal gravimetric analysis (TGA) technique. The order of the thermal stability is TiO2 > TiO2-PANI > PANI.  The crystal lattice characteristics were confirmed using Transmission electron microscopy (TEM). The surface area measurements were confirmed from the Brunauer-Emmett-Teller (BET) study and were employed for the evaluation of the photocatalytic efficiency of both, TiO2 nanoparticles and TiO2-PANI nanocomposite catalysts. The energy dispersive spectroscopy (EDS) study was employed for elemental detection of the fabricated materials. While Raman spectroscopy was employed for the chemical structure and the phase characteristics of the materials. The standard conditions for the degradation of the CF dye were 8 g/L of catalyst dosage, 20 mg/L of dye concentration, and a pH of 7. The TiO2-PANI nanocomposite exhibited superior efficiency as compared to pure TiO2 nanoparticles, achieving almost 100 % degradation in just 40 minutes.  
Wed Abed,
Volume 21, Issue 2 (6-2024)
Abstract

Silver/polyvinyl alcohol (Ag/PVA) nanocomposites were fabricated via an electrochemical method. Silver nanoparticles (AgNPs) with varying grain sizes were directly synthesized within PVA polymer matrices at deposition times of 15, 30, 45, 60, and 120 minutes. The integration of AgNPs within the PVA matrix was confirmed through Transmission Electron Microscopy (TEM) and optical absorbance measurements. X-ray Diffraction (XRD) analysis demonstrated the face-centered cubic structure of AgNPs. Furthermore, these prepared nanocomposites exhibited significant antibacterial properties against Bacillus subtilis and Pseudomonas pneumonia, as well as antifungal activity against Alternaria alternata. Remarkably, the AgNPs/PVA nanocomposite exhibited outstanding antifungal efficiency, resulting in an impressive inhibition zone of up to 47 mm.
 
Ahad Saeidi, Sara Banijamali, Mojgan Heydari,
Volume 21, Issue 2 (6-2024)
Abstract

This study explores the fabrication, structural analysis, and cytocompatibility of cobalt-doped bioactive glass scaffolds for potential applications in bone tissue engineering. A specific glass composition modified from Hench's original formulation was melted, quenched, and ground to an average particle size of 10 μm. The resulting amorphous powder underwent controlled sintering to form green bodies and was extensively characterized using simultaneous differential thermal analysis (DTA), Raman spectroscopy, and Fourier Transform Infrared analysis (FTIR). After mixing with a resin and a dispersant, the composite was used in digital light processing (DLP) 3D printing to construct scaffolds with interconnected macropores. Thermal post-treatment of 3D printed scaffolds, including debinding (Removing the binder that used for shaping) and sintering, was optimized based on thermogravimetric analysis (TG) and the microstructure was examined using FE-SEM and XRD. In vitro bioactivity was assessed by immersion in simulated body fluid (SBF), while cytocompatibility with MC3T3 cells was evaluated through SEM following a series of ethanol dehydrations. The study validates the fabrication of bioactive glass scaffolds with recognized structural and morphological properties, establishing the effects of cobalt doping on glass behavior and its implications for tissue engineering scaffolds. Results show, Low cobalt levels modify the glass network and reduce its Tg to 529 oC, while higher concentrations enhance the structure in point of its connectivity. XRD results shows all prepared glasses are amorphous nature, and DTA suggests a concentration-dependent Tg relationship. Spectroscopy indicates potential Si-O-Co bonding and effects on SiO2 polymerization. Cobalt's nucleating role promotes crystalline phases, enhancing bioactivity seen in rapid CHA layer formation in SBF, advancing the prospects for bone tissue engineering materials.
Ramin Dehghani, Seyed Mojtaba Zebarjad,
Volume 21, Issue 3 (9-2024)
Abstract

Acrylic resins are one of the most important thermoplastic resins used in various industries due to their significant properties. However, they are inherently brittle and addition plasticizers to them is very common. In this study, role of both Polyethylene Glycol (PEG) and Triacetin on the mechanical properties of acrylic resin have been investigated. To do so tensile test, bending and wear tests have been performed. To achieve the optimal mixture of plasticizers, a tensile test has been carried out, and the best percentage of the mixture has been determined. Subsequently, bending and wear tests were conducted, which showed a significant increase in the bending strength of the acrylic resin after the addition of plasticizers. Furthermore, it was found that the abrasion mechanism of the resin was significantly altered compared to its pure state.
 
Ghada Ben Salah,
Volume 21, Issue 3 (9-2024)
Abstract

This study reported the biological changes occurring after γ-irradiation of in vivo rat model and the osteochondral protective effect of Gelatine-Chitosan-Ginger (GEL-CH-GING). The results showed that Electron Paramagnetic Resonance (EPR) Spectroscopy of GEL-CH-GING showed two paramagnetic centres which correspond to g=2.19 and g= 2.002. The Fourier transform infrared spectroscopy (FTIR) analyses revealed an increase in peak intensity at C–H chains, as well as, C=O carbonyl groups. The X-ray diffraction (XRD) analysis showed no change of crystallinity. After gamma ray exposure, the rat groups have received an osteochondral defect and then were treated with GEL-CH-GING composite. Sixty days post-surgery, a significant reduction in thiobarbituric acid-reactive compounds (TBARs) was seen when compared to non-implanted rat group. Concerning oxidative stress status, GEL-CH-GIN significantly improved Superoxide Dismutase (SOD) 76 nmol/l, Catalase (CAT) 0.79 nmol/l, and Glutathione Peroxidase (GPx) 1.77 nmol/l activities in osteochondral tissue. Regarding the histomorphometric parameters of cartilaginous tissue (nCg.Th, µm), (cCg.Th, µm), (Cg.Th, µm), irradiated-GEL-CH-GIN group showed a significant increase as compared to irradiated group with 116, 74 and  188 µm, respectively (p<0.01). The microanalysis showed a high percentage of O and C in the regenertaed osteochondral tissue and indicated the deposition of novel collagen matrix. The biomechanical behaviour showed a significantly enhanced hardness measurement (1.73±0 .029 VH, p<0.05) when compared with that of irradiated group
Biochemical markers suggested an osteocartilage repair capacity.  In fact, the levels of IL-1β, IL-6, TNF-α and VEGF in the implanted rat with GEL-CH-GING composite exhibited 51±3.48, 30.05±5.18, 65.12±4.33 and 40.42±3.32 ng/l, respectively. Our findings suggested that GEL-CH-GING composite might have promising potential applications for cartilage healing.
Hadi Sharifidarabad, Alireza Zakeri, Mandana Adeli,
Volume 21, Issue 3 (9-2024)
Abstract

The sensitivity of lead dioxide coating properties to the deposition conditions and electrolyte composition has allowed the preparation of coatings with different properties for different applications. In this study, the effects of electrolyte additives on the electrodeposition process were investigated using electrochemical measurements such as cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy. The results showed that the presence of fluoride ions significantly reduce the possibility of TiO2 formation. The addition of copper ions not only prevents lead loss at the cathode, but also leads to the formation of copper oxide on the surface at initial stages, which hinders nucleation of PbO2. The presence of sodium dodecyl sulfate (SDS) also interferes with the nucleation process as it occupies active nucleation sites. The α-PbO2 interlayer prevents copper oxidation and solves the problem of lead dioxide nucleation. Finally, it was found that the simultaneous use of all additives together with the α-PbO2 interlayer has a positive effect on the coating process.
Dewi Qurrota A'yuni, Hadiantono Hadiantono, Velny Velny, Agus Subagio, Moh. Djaeni, Nandang Mufti,
Volume 21, Issue 3 (9-2024)
Abstract

Rice husk carbon by-product from the industrial combustion is a promising source to produce a vast amount of activated carbon adsorbent. This research prepared rice husk-activated carbon adsorbent by varying the concentration of potassium hydroxide solution (5, 10, 15, 20 % w/v) and activation time (2, 4, 6, 8 hours). Fourier-transform infrared spectral characterization (FTIR) indicated a significant effect before and after activation, especially the presence of hydroxyl groups. Based on the iodine adsorption, the specific surface area of the produced-activated carbon was approximately 615 m2/g. Experimental results showed that increasing potassium hydroxide concentration and activation time increases the water vapor adsorption capacity of the activated carbon. Compared with the rice husk carbon, the KOH-activated carbon enhanced the water vapor adsorption capacity to 931%. In the adsorption observation, changing the temperature from 15 to 27 ℃ caused a higher water vapor uptake onto the activated carbon. Two adsorption kinetics (pseudo-first- and pseudo-second-order models) were used to evaluate the adsorption mechanism. This research found that rice husk-activated carbon performed a higher water vapor adsorption capacity than other adsorbents (silica gel, zeolite, and commercially activated carbon).
Muddukrishnaiah Kotakonda, Sajisha V.s, Aiswarya G, Safeela Nasrin Pakkiyan, Najamol A Alungal, Mayoora Kiliyankandi K, Divya Thekke Kareth, Naheeda Ashraf Verali Parambil, Saranya Sasi Mohan, Renjini Anil Sheeba, Sarika Puthiya Veettil, Dhanish Joseph, Nishad Kakkattummal, Afsal Bin Haleem Mp, Safeera Mayyeri, Thasneem Chemban Koyilott, Nasiya Nalakath, Samuel Thavamani B, Famila Rani J, Aruna Periyasamy, Chellappa V Rajesh, Rameswari Shanmugam, Marimuthu Poornima, Tina Raju, Roshni E R, Sirajudheen Mukriyan Kallungal, Lekshmi Ms Panicker, Saranya K G, Shilpa V P,
Volume 21, Issue 3 (9-2024)
Abstract

Biogenic synthesis of papain-conjugated copper metallic Nanoparticles and their antibacterial and antifungal activities Papain metallic conjugated nanoparticles (Papain-CuNPs) were synthesised using Papain and CuSO4.5H2O. Papain-CuNPs were characterized using UV-visible spectroscopy, FT-IR, HR-TEM, XRD, FE-SEM, zeta potential, and a zeta sizer. The antibacterial activity of papain-CuNPs against human infectious microorganisms (Citrobacter spp, Pseudomonas aeruginosa and Candida albicans) was investigated. The mechanism of action of papain-CuNPs was evaluated using FE-SEM and HRTM. UV spectroscopy confirmed the plasma resonance (SPR) at 679 nm, which indicated the formation of papain-CuNPs. The FT-IR spectrum absorbance peaks at 3927, 3865, 3842, 3363, 2978, and 2900 cm-1 indicate the presence of O-H and N-H of the secondary amine, and peaks at 1643 and 1572 cm-1 represent C=O functional groups in Papain-CuNPs. EDAX analysis confirmed the presence of copper in the papain-CuNPs. The zeta potential (-42.6 mV) and zeta size (99.66 d. nm) confirmed the stability and size of the nanoparticles. XRD confirmed the crystalline nature of the papain-CuNPs. FE-SEM and HRTM showed an oval structure, and the nano particles' 16.71244–34.84793 nm. The synthesized papain-NPs showed significant antibacterial activity against clinical P. aeruginosa (15 mm). MIC 125 µg/ml) showed bactericidal activity against P. aeruginosa and the mechanism of action of Papain-NPs was confirmed using an electron microscope by observing cell damage and cell shrinking. Papain-CuNPs have significant antibacterial activity and are thus used in the treatment of P. aeruginosa infections
Majid Tavoosi,
Volume 21, Issue 3 (9-2024)
Abstract

The present study focuses on the phase and structural features of MnAl intermetallic compound during solid-state synthesis. In this regard, the milling process was done in differentMn50+xAl50-x (0<x<7.5)powder mixtures and the prepared samples were evaluated using X-ray diffractometer, scanning and transmission electron microscopy, differential thermal analysis and vibrating sample magnetometer. The results showed that the τ-MnAl magnetic phase with L10 structure could not be formed during the milling and low temperature annealing. During milling process, Al atoms dissolve in Mn network and a single β-Mn supersaturated solid solution (SSSS) form. The β-Mn (SSSS) phase is unstable and transforms into the icosahedral quasi-crystal as well as γ2-Al8Mn5 and β-Mn stable phases during subsequent annealing.
 
Mahnaz Dashti, Saeid Baghshahi, Arman Sedghi, Hoda Nourmohammadi,
Volume 21, Issue 3 (9-2024)
Abstract

Abstract
The power line insulators are permanently exposed to various environmental pollutants such as dust and fine particles. This may lead to flashovers and therefore widespread power blackouts and heavy economic damage. One way to overcome this problem is to make the insulator surface superhydrophobic. In this research, the superhydrophobic properties of the insulators were improved by applying room-temperature cured composite coatings consisting of epoxy and hydrophobic nano-silica particles. Either octadecyl trichlorosilane (ODTS) or hexamethyldisilazane (HMDS) was used to coat the silica nanoparticles and make them hydrophobic. Then, the hydrophobic silica was added to a mixture of epoxy resin and hardener. The suspension was applied on the surfaces of a commercial porcelain insulator and cold cured at ambient temperature. The coating increased the water contact angle from 50° to 149°. Even after 244 h exposure to the UV light, the samples preserved their hydrophobic properties. The adhesion of the coating was rated as 4B according to the ASTM D3359 standard. The coating decreased the leakage current by 40% and increased the breakdown voltage by 86% compared to the uncoated sample and showed promise for making power line insulators self-cleaning.
 
Tumelo Moloi, Thywill Cephas Dzogbewu, Maina Maringa, Amos Muiruri,
Volume 21, Issue 3 (9-2024)
Abstract

The stability of microstructure at high temperatures is necessary for many applications. This paper presents investigations on the effect of changes in temperature on the microstructures of additively manufactured Ti6Al4V(ELI) alloy, as a prelude to high temperature fatigue testing of the material. In the present study, a Direct Metal Laser Sintering (DMLS) EOSINT M290 was used to additively manufacture test samples. Produced samples were stress relieved and half of these were then annealed at high temperatures. The samples were then heated from room temperature to various temperatures, held there for three hours and thereafter, cooled slowly in the air to room temperature. During tensile testing, the specimens was heated up to the intended test temperature and held there for 30 minutes, and then tensile loads applied to the specimens till fracture. Metallographic samples were then prepared for examination of their microstructures both at the fracture surfaces and away from them. The obtained results showed that changes in temperature do have effects on the microstructure and mechanical properties of Ti6Al4V(ELI) alloy. It is concluded in the paper that changes in temperature will affect the fatigue properties of the alloy.
Hossein Momeni, Sasan Ranjbar Motlagh,
Volume 21, Issue 3 (9-2024)
Abstract

The present work deals with the hot deformation behavior of commercial Nb alloy C-103 and its microstructure evolution during uniaxial compression tests in the temperature range of 700-1100 °C and the strain rate range of 0.001-0.4 s-1. Strain rate sensitivity, calculated from the compression tests data, was almost constant and showed a negative value in the temperature range of 700-900 °C but increased significantly beyond 900 °C. Dynamic strain aging was found to have a predominant effect up to 900 °C, beyond which dynamic recovery and oxidation influenced the compressive properties. The microstructure of the deformed samples showed indications of dynamic recrystallization within the high strain rate sensitivity domain and features of flow instability in the regime of low strain rate sensitivity. The 950–1000 °C temperature range and strain rate range of 0.001-0.1 s-1 were suggested as suitable hot deformation conditions. The constitutive equation was established to describe the alloy's flow behavior, and the average activation energy for plastic flow was calculated to be 267 kJ/mol.
 

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