Namrata Saxena, Varshali Sharma, Ritu Sharma, Kamlesh Kumar Sharma, Kapil Kumar Jain,
Volume 18, Issue 2 (6-2021)
Abstract
The work reported in this paper was focused on the investigation of surface morphological, microstructural, and optical features of polycrystalline BaTiO3 thin film deposited on p-type Si < 100 > substrate using e-beam PVD (physical vapor deposition) technique. The influence of annealing over the surface morphology of the thin film was analyzed by X-ray diffraction, atomic force microscopy and scanning electron microscopy characterization methods. When the annealing temperature was increased from as-deposited to 800 °C there was a significant growth in the grain size from 28.407 nm to 37.89 nm. This granular growth of BaTiO3 made the thin film appropriate for nanoelectronic device applications. The roughness of the annealed film got increased from 31.5 nm to 52.8 nm with the annealing temperature. The optical bandgap was computed using Kubelka-Munk (KM) method which got reduced from 3.93 eV to 3.87 eV for the as-deposited to the 800 °C annealed film. The above reported properties made the annealed film suitable for optoelectronic applications. For polycrystalline BaTiO3 thin film the refractive index varied from 2.2 to 1.98 from 400 to 500 nm and it was 2.05 at 550 nm wavelength. The broad peaks in Raman spectra indicated the polycrystalline nature of the thin film. It had been also observed that with the annealing temperature the intensity of the Raman bands got increased. From these results, it was proved that annealing significantly improved the crystallinity, microstructural, surface morphological and optical features of the barium titanate thin film which made it suitable as sensors in biomedical applications as it is cost-effective, lead-free and environment friendly material.
Masumeh Mohammadi, Hamidreza Rezaei Ashtiani,
Volume 18, Issue 2 (6-2021)
Abstract
The hot deformation behavior of the heat-treated AA6061 and AA 6063 aluminum alloys by T6-1, T6-2 artificial aging treatment, and O annealing treatment were studied by compression testing over a temperature range of 350–550
and strain rates of 0.005-0.1 s
-1. It was observed that the flow stresses of the studied aluminum alloys treated by the T6-1 and T6-2 heat treatments were significantly higher than those of the O annealing treatment. Moreover, the stress-strain curves of the heat-treated alloys by the T6-1, T6-2, and O heat treatments demonstrated significant softening during deformation at the lowest strain rate under any of the deformation conditions. For several strains, the activation energy of hot deformation was specified and obtained to vary significantly with strain for the heat-treated alloys by the T6-1 and T6-2 treatments. The stress-strain data calculated from a linear equation, with strain-dependent parameters, shows a great fit with the experimental data for the heat-treated aluminum alloys.
Amir Mostafapour, Milad Mohammadi, Ali Ebrahimpour,
Volume 18, Issue 2 (6-2021)
Abstract
A full factorial design of experiment was applied running 36 experiments to investigate the effects of milling parameters including cutting speed with three levels of 62.83, 94.24 and 125.66 m/min, feed rate with three levels of 0.1, 0.2 and 0.3 mm/tooth, cutting depth with two levels of 0.5 and 1 mm and machining media with two levels, on surface integration properties of magnesium AZ91C alloy such as grain size, secondary phase percent, surface microhardness and surface roughness. In all cases, a fine grained surface with higher secondary phase sediment and microhardness obtained comparing the raw material. According to analysis of variance results, the most effective parameter on grain size, secondary phase percent and microhardness was cutting depth and the most effective parameter on surface roughness was feed rate. although the grain size in all machined samples was smaller than that of the raw material but due to the dual effect of cryogenic conditions, which both cool and lubricate and reduce the temperature and strain rate at the same time, the direct effect of this parameter on grain size was not significant. Also, the all interaction effects of parameters on grain size and microhardness were significant.
Mohammad Ali Maghsoudlou, Reza Barbaz Isfahani, Saeed Saber-Samandari, Mojtaba Sadighi,
Volume 18, Issue 2 (6-2021)
Abstract
The low velocity impact (LVI) response of pure and glass fiber reinforced polymer composites (GFRP) with 0.1, 0.3 and 0.5 wt% of functionalized single-walled carbon nanotubes (SWCNTs) was experimentally investigated. LS-DYNA simulation was used to model the impact test of pure and incorporated GFRP with 0.3 wt% of SWCNT in order to compare experimental and numerical results of LVI tests. All tests were performed in two different levels of energy. In 30J energy, the specimen containing 0.5 wt% SWCNT was completely destructed. The results showed that the incorporated GFRP with 0.3 wt% SWCNT has the highest energy absorption and the back-face damage area of this sample was smaller than other specimens. TEM images from specimens were also analyzed and showed the incorporation of well-dispersed 0.1 and 0.3 wt% of SWCNT, while in specimens containing 0.5 wt% of CNT, tubes tended to be agglomerated which caused a drop in LVI response of the specimen. The contact time of impactor in numerical and experimental results was approximately equal; however, the maximum contact forces in LS DYNA simulation results were higher than the experimental results which could be due to the fact that in the numerical modeling, properties are considered ideal, unlike in experimental conditions.
Mahdi Alishavandi, Mahnam Ebadi, Amir Hossein Kokabi,
Volume 18, Issue 2 (6-2021)
Abstract
Friction-Stir Processing (FSP) was applied on AA1050 Aluminum Alloy (AA) to find the highest mechanical properties among 28 combinations of the rotational and traverse speed (800-2000 rpm and 50-200 mm.min-1) and four different tool probe shapes (threaded, columnar, square and triangle). To this aim, the AA standard sheet went through a single pass of FSP. The 1600 rpm and 100 mm.min-1 with threaded tool probe was chosen as the best combination of rotational and traverse speed. Grain size at the Stirred Zone (SZ) was studied using Optical Microscopy (OM). The results showed that the SZ’s grain size was refined from 30 μm down to about 12 μm due to dynamic recrystallization during FSP. The processed sample exhibited improved hardness, yield stress, ultimate tensile strength, elongation up to 65, 80, 66, and 14%, respectively, compared to the annealed AA sample. Studying fractographic features by OM and field emission scanning electron microscope (FESEM) revealed a dominantly ductile fracture behavior.
Najwa Gouitaa, Lamcharfi Taj-Dine, Bouayad Lamfaddal, Abdi Farid, Mohamed Ounacer, Mohammed Sajieddine,
Volume 18, Issue 2 (6-2021)
Abstract
Prabhakar Kuppahalli, Ramaiah Keshavamurthy, Padmanathan Sriram, Ahobal Narayana,
Volume 18, Issue 2 (6-2021)
Abstract
The present investigation aims to synthesize RB031, RB032 manganese bronze alloys equivalent to HTB1 and HTB2 alloys with additions of silicon and to characterize them with the help of Microstructure and Mechanical properties. The methodology involves melting of alloy’s in a 300kg Coreless medium frequency induction furnace, casting them in Permanent and Shell moulds with optimum values of Zinc equivalent and retaining their high mechanical properties. The study includes the development and mechanical property measurements of the alloys synthesized. Characterization has been carried out using Optical Microscopy and Scanning Electron Microscopy with EDAX analysis for investiagtion of compositional variations and inquisition of hardness measurement & tensile properties. It is concluded from this work that RB032 alloy cast in Permanent moulds has superior hardness and tensile properties compared to Shell moulds and far exceeds that of NAB (AB2) alloys processed under similar conditions. Further, this investigation includes grain refinement by suitable Heat treatment studies to combat Hot Tearing since the strength is adequate enough with RB032 exhibiting higher hardness than other two alloys.
Rahida Wati Sharudin, Nik Salwani Md Azmi, Muhammad Shafiq Mat Shayuti, Masahiro Ohshima,
Volume 18, Issue 2 (6-2021)
Abstract
The control of silicone rubber’s viscoelastic properties namely loss factor, storage and loss moduli during crosslinking are crucial as its malleable behaviour changes differently under different conditions and affecting the final product. Hence, it becomes the objective of this study to investigate the rheological behaviour of silicone rubber cured under different formulation ratios with platinum catalysts and triethylamine, methanol & ethanolamine solvent. Measurement was conducted for the silicone rubber to crosslinker ratios of 2.5:7.5, 5:5, 7.5:2.5 and 10:1 at different elevated temperatures, and for the silicone rubber with triethylamine, methanol and ethanolamine at different angular frequencies. While the crossover of storage and modulus curve which signifies a gel point was not observed at higher ratios of platinum used across the temperature range of 25 – 100°C, it was found at 89°C and 95°C with the formulation ratios of 10:1 and 7.5:2.5, respectively. On the other hand, the crossover point was observed for silicone rubber at 100 s-1 for triethylamine, 3 s-1 and 100 s-1 for methanol, and 70 s-1 alongside 290 s-1 for ethanolamine. The presence of gel point indicates that crosslinking of silicone rubber successfully took place and this study proves that controlling the crosslinking behaviour was possible.
Saeid Karimi, Akbar Heidarpour, Samad Ghasemi,
Volume 18, Issue 2 (6-2021)
Abstract
In this research, expanded graphite (EG) was successfully fabricated using a simple ball milling process followed by hydrofluoric (HF, 10 wt. %) leaching. The effects of ball milling time (0-15 h) and leaching time (1-24 h) on the exfoliation of graphite were examined by XRD and Raman spectra. Furthermore, the morphological evaluation of the obtained expanded graphite samples was carried out by scanning electron microscopy (SEM). The XRD results of the ball-milled and HF treated samples showed a slight peak shift and broadening of (002) plane for expanded graphite compared to the precursor and HF-treated samples. Moreover, the intensity of the (002) planes remarkably decreased by the ball milling process but remained constant after HF treatment. Raman spectra of the samples confirmed the ordering process only in HF-treated specimens. Moreover, the intensity ratio of 2D1 to 2D2 band gradually increased with enhancing the HF treatment time up to 5 hours, indicating a decrement in the number of graphite layers by leaching in the HF solution.
Farid Lekmine, Hachemi Ben Temam, Elhachmi Temam,
Volume 18, Issue 3 (9-2021)
Abstract
Nickel phosphorus alloy coatings were prepared by electrodeposition route from sulfate electrolyte bath at various current densities. SEM studies reveal spherical grains covered the entire surface with uniform distribution. EDX results showed a linear increase of P content in the developed deposits with current density and therefore, enhancing the grains size and drop of the hardness values. XRD studies reveal monocrystalline orthorhombic alloys at a low amount of phosphorus (10.88 wt. %). Corrosion tests show that 1 A.dm-2 is the best applied current density giving the nobler Ecorr (-171.4 mV) and the lower icorr (4.64 µA/cm2).
Mohammed Ruhul Amin Bhuiyan, Hayati Mamur,
Volume 18, Issue 3 (9-2021)
Abstract
Carbon-based chemical substances persistence can contribute to adverse health impacts on human lives. It is essential to overcome for treatment purposes. The semiconducting metal oxide is Zinc Oxide (ZnO), which has excellent biocompatibility, good chemical stability, selectivity, sensitivity, non-toxicity, and fast electron transfer characteristics. The ZnO nanoparticles are more efficient compared to other metal oxide materials. Thus, the nanoparticles are in the present research situation to receive increasing attention due to their potential performance of the human body to feel comfortable. The nanoparticles become more promising for biomedical applications through the development of anticancer agents to recovery different types of malignant cells in the human body. The ZnO nanoparticles can be the future potential materials for biomedical applications. The purpose of this paper is to review the cost-effective approach to synthesize the ZnO nanoparticles. Moreover, these ideas can develop for synthesized ZnO biomaterial to perform easily up-scaled in biomedical applications.
Umarfarooq Maktedar Abdulkhadar, Patil Somalinganagouda Shivakumargouda, Gonal Basavaraja Veeresh Kumar, Krishnaraja Govinda Kodancha,
Volume 18, Issue 3 (9-2021)
Abstract
Residual stress measurement is of utmost importance for the safety and reliability of engineering components and has been an active area of scientific research. Relaxation techniques such as hole drilling, slitting and ring core method are widely applied semi destructive techniques for residual stress measurements in polymer composites. This article reviews the recent literature on the measurement of residual stress in polymer composite by employing the above-mentioned relaxation techniques. This article summarizes the categories of residual stresses, causes of formation, techniques of measurements and also briefly outlines the chronological developments of the Hole drilling and slitting method. The article also provides a comparative summary of these relaxation methods.
Saeed G. Shabestari, Sahar Ashkvary, Farnaz Yavari,
Volume 18, Issue 3 (9-2021)
Abstract
The influence of melt superheating treatment on the solidification characteristics and microstructure of Al–20%Mg2Si in-situ composite has been investigated. The results revealed that melt superheating temperature has a significant effect on solidification parameters and morphology of primary Mg2Si particles. Solidification parameters acquired using cooling curve thermal analysis method, indicate that both nucleation temperature and nucleation undercooling of primary Mg2Si particles increase by increasing melt superheating temperature, while recalescence undercooling decrease under the same condition. Also, based on the microstructural evaluations, melt superheating treatment can refine primary Mg2Si particles and alter their morphology from dendritic shape to more spherical shape and the eutectic microstructure of a-Al + Mg2Si becomes finer and the distance between eutectic layers becomes smaller.
Najwa Gouitaa, Lamcharfi Taj-Dine, Abdi Farid , Ahjyaje Fatima Zahra,
Volume 18, Issue 3 (9-2021)
Abstract
In this study we have synthesis the Zr substituted BaTi0.80Fe0.20O3 ceramics at different content of Zr from x=0.00 to 0.10 by using the solid-state route. The room temperature X-ray diffraction results confirmed the coexistence of the two tetragonal and hexagonal phases for x ≤ 0.050 of Zr content. While above 0.050 the hexagonal phase disappears in benefit of tetragonal phase. The Raman results confirmed the formation of these phases obtained with XRD. The scanning electron micrographs consist of both spherical and straight grain forms for x=0.000 to 0.075, and only spherical grain form for x=0.100 attributed to the tetragonal phase. Also, the grain size increases accompanied with a decrease in density of ceramics with increasing Zr content up to 0.050 then decreases accompanied with an increase in density. Detailed studies of dielectric permittivity measurement have provided a presence of two anomalies Te and TR-O at different temperatures, with a relaxation phenomenon and diffuse behavior which is very important for ceramic at x=0.075 of Zr content. The dielectric permittivity values of the two anomalies of Zr substituted BaTi0.80Fe0.20O3 ceramics increase with increase of Zr content and the dielectric loss is minimal at x=0.100 of Zr content. The conductivity increases with the increasing of Zr substitution from 0.025 to 0.075 levels while for x = 0.100 the dielectric conductivity decreases. And the Cole-Cole analysis indicates a negative thermal resistivity coefficient (NTCR) behavior of these materials and an ideal Debye-type behavior.
Rabah Bobaaya, Omar Allaoui, Mokhtar Djendel, Samir Benaniba,
Volume 18, Issue 3 (9-2021)
Abstract
Coatings based on chromium borides and chromium carbides are commonly employed in applications requiring mechanical performance, such as high hardness and low friction coefficient, as well as corrosion resistance. In this work, we made layers of chromium borides and chromium carbides on the surface of low carbon steel through some specific treatments. For chromium borides, the boriding treatment in a solid medium at 900 °C for 4 hours followed by chromium electroplating on the steel surface and finally the application of annealing treatment at temperatures at 950 °C for 1 and 2 hours. For chromium carbides, the cementation in a solid medium followed by electroplating of chromium on the surface and finally the application of annealing treatment at temperatures between 500 and 1100 °C for 1 hour. The obtained results show that, in the first case, boron diffusion and chromium deposition lead to chromium borides on the treated surface. Similarly, for the second case, the cemented layer and the chromium deposited on the surface combine to form chromium carbides on the treated surface after annealing. The characteristics of the chromium borides and chromium carbides obtained are very similar to those of chromium borides and chromium carbides obtained by other processes.
Amirhosein Paryab, Toktam Godary, Sorosh Abdollahi, Mohsen Anousheh, Adrine Malek Khachatourian,
Volume 18, Issue 3 (9-2021)
Abstract
Silicon oxycarbide (SiOC) materials derived from silicone attracted great attention for their superior high-temperature behavior. In the present study, Si(Ti)OC and Si(Ti,Al)OC nanocomposites, in which alkoxide precursors were used with the main silicone precursor, have been compared with SiOC material. Although in SiOC, C was bonded with Si in a carbon-rich SiOC phase, X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) showed that TiC was the preferred state for C atoms upon adding Ti into the system. This claim was also substantiated by Raman spectroscopy, where adding Ti into the system lowered the intensity of the D band, indicating the high affinity of C to form crystalline TiC. In the Si(Ti,Al)OC nanocomposites synthesized by adding AlCl3 into the Si(Ti)OC system, mullite nanocrystals formed a superlattice structure with TiC. UV-vis spectra of the nanocomposites showed Si(Ti,Al)OC with mullite-TiC superlattice had a larger bandgap compared with Si(Ti)OC with only TiC nanocrystals.
Hamed Tavakoli, Mohammad Reza Aboutalebi, Hossein Seyedein, Seyed Nezameddin Ashrafizadeh,
Volume 18, Issue 3 (9-2021)
Abstract
Solvent extraction of samarium from aqueous solutions by two different types of extractants, namely D2EHPA and PC88A, in kerosene was investigated. Through identification of speciation diagrams, the chemically stable complexes of samarium in different acidic solutions (H2SO4, HCl and HNO3) were first investigated. Regarding the various types of samarium species in sulfate medium in comparison with other acidic environments, H2SO4 and HNO3 media were chosen to examine the extraction behavior of samarium complexes. Thermodynamic parameters of samarium extraction reactions by D2EHPA and PC88A from aqueous solutions of HNO3 and H2SO4 were calculated as ∆G∘ (D2EHPA-HNO3), , ∆G∘ (D2EHPA-H2SO4) , ∆G∘ (PC88A-HNO3), ∆G∘ (PC88A-H2SO4) equal to -5.58, 3.40, 6.70 and 14.26, and respective ΔHº values equal to -9.38, -2.75, 4.01 and 16.95 kJ/mol, respectively. According to the results, D2EHPA seemed to be a more efficient extractant than PC88A and nitric aqueous solution was a better media than the sulfuric one. The synergistic effect of binary extractants revealed that synergistic factors were 2.94 and 5.74 in sulfuric and nitric solutions, respectively, for a D2EHPA:PC88A ratio of 2:3. The compositions of extracted complexes by D2EHPA and PC88A in sulfuric and nitric solutions were SmH3A6 and SmH3B6, respectively. Thermodynamic parameters of extraction reactions were calculated to be Ke equal to 9.513, 0.254, 0.067, and 0.003 and ∆S∘ (D2EHPA-HNO3), , ∆S∘ (D2EHPA-H2SO4) , ∆S∘ (PC88A-HNO3), ∆S∘ (PC88A-H2SO4) equal to -12.75, -20.64, -9.03, and 9.03 (J mol-1), respectively.
Hilal Acay, Ayfer Yıldırım, Ayşe Baran,
Volume 18, Issue 3 (9-2021)
Abstract
Gold nanoparticles (AuNP) were synthesized using edible mushroom Russula delica (RD) in this study. Possibilities to evaluate these synthesized nanoparticles (RD-AuNPs) as bioactive substances were investigated. Characterization of synthesized RD-AuNPswere characterized via UV-vis, XRD, FTIR, EDX. In spherical view, RD-AuNPs with a crystal size of 34.76 nm were synthesized. As a result, fungal systems used for nanomaterial biosynthesis as an effective alternative to chemical synthesis can be used in different biotechnological and medical applications. RD-AuNPs produced by green synthesis can be evaluated in this context.
Usha Vengatakrishnan, Kalyanaraman Subramanian, Vettumperumal Rajapand, Dhineshbabu Nattanmai Raman,
Volume 18, Issue 3 (9-2021)
Abstract
Copper oxide (CuO) nanostructure particles were prepared using KOH/NaOH catalyst by low cost precipitation method and characterized by powder X-ray diffraction (PXRD), scanning electron microscope (SEM) and energy dispersive X-ray spectra (EDX) analysis. The photocatalytic dye degradation study of pure CuO nanostructure particles are analysed against two azo dyes (Direct black 38 (Black-E) and Congo red) under ultraviolet (UV) and solar irradiation. The release of major active species (*OH) in the photocatalytic degradation by as prepared CuO nanostructure particles were investigated by photoluminescence (PL) spectra with two different excitation wavelength (325and 355nm). The band gap of CuO nanostructure particles was calculated from diffuse reflectance spectra. The photocatalytic effect of CuO nanostructure particles is confirmed from the UV – Vis and photoluminescence spectra and also, further confirmed from the kinetic studies under UV and solar radiations. The photocatalytic degradation results revealed that 16.35% and 7.5% of black E and Congo red dye was degraded under UV, while it was 47.2% and 17.6% under solar light. The influence of pH on the photodegradation and change in the reaction temperature under solar irradiation were also analysed
Mitra Ghannadi, Hediye Hosseini, Bagher Mohammad Sadeghi, Bahman Mirzakhani, Mohammad Tahaaha Honaramooz,
Volume 18, Issue 3 (9-2021)
Abstract
The objective of the present paper is to investigate the effects of rapid heating and cryogenic cooling on on the microstructure and tensile properties of Al-Cu-Mg. The specimens were subjected to three heat treatment cycles in which the Infrared heating (IR) were used as the heating medium at the ageing stage, and the liquid nitrogen and water were used as the quenching mediums. The ageing temperature and time were 190⁰C and from 2 hours to 10 hours, respectively.The results indicated that by using IR at the ageing stage, the hardening rate enhanced because the rapid heating via this method leads to faster diffusion of the alloying elements. Moreover, the high density of nano-sized precipitates formed during ageingleads to higher strength and suitable ductility. Cryogenic treatment showed a negligible effect on both microstructure and tensile properties; however, it improved ductility. Overall, the combination of a high heating rate and cryogenic treatment led to the highest mechanical properties. SEM micrograph of the fracture surface of alloy demonstrated that in Cryogenic treatment+Artificial Ageing (CAA) condition, the surface had been fully covered by deep dimples in contrast to the Cryogenic treatment+Infrared Heating (CIR) and Water-Quench+ Infrared Heating (QIR) conditions which their dimples were shallow and also some facets were observed.
