XML
-
-
List of Articles
-
Open Access Article
1 - Synthesis of Molybdenum disulfide solid lubricant coating on steel using Thermal-diffusion method
mehdi akbarzadeh Morteza ZanrahimiMolybdenum disulfide (MoS2) is one of the most solid lubricants applied on surfaces under friction condition in different ways. In this study, MoS2 coatings was applied on 316 stainless steel using thermal diffusion method at various temperatures and times. Coatings pro MoreMolybdenum disulfide (MoS2) is one of the most solid lubricants applied on surfaces under friction condition in different ways. In this study, MoS2 coatings was applied on 316 stainless steel using thermal diffusion method at various temperatures and times. Coatings properties were investigated using SEM, EDX, XRD and FTIR, Hardness Tester and Roughness tester. The results indicated formation of a uniform layer on the surface that contains MoS2 and MoO3-X phases. Coatings have thickness of 20-50 µm and grain size of 400-1000 nm and hardness of 350- 550 HV. Also in this study, the kinetics of diffusion layer between substrate and coating has been investigated. the kinetics of diffusion layer between substrate and coating has been investigated. It was found that thickness of diffusion layer changes with time at constant temperature follow from parabolic equation.The thickness of diffusion layer changes with time at at constant temperature follow from parabolic equation. Manuscript profile -
Open Access Article
2 - Investigation of the factors affecting the foam ability of SiO2-Al2O3-MgO-CaO glass
سوسن هاشمی نیاIn the present work, Foaming and crystallisation behaviors of compacted glass powders based on a diopside glass-ceramic composition were investigated through the sintering route. The foaming agent was 2wt.%SiC particles.The results indicated that the lack of foaming of MoreIn the present work, Foaming and crystallisation behaviors of compacted glass powders based on a diopside glass-ceramic composition were investigated through the sintering route. The foaming agent was 2wt.%SiC particles.The results indicated that the lack of foaming of the base glass was due to high softening point and crystallization tendency . Therefore the effect of PbO and B2O3 on the foaming ability of glasses was investigated. According to our finding, addition of PbO improved foaming ability ,via improving wettability of glass - SiC particles,increasing of optical basicity and widening the temperature interval between dilatometric softening point and the onset of crystallization temperature. The glass- SiC wetting angle was decreased from 85° for the lead-free glass to 55° for the glass that contains 15 wt.% PbO. While with addition of B2O3, foaming ability of base glass in spite of widened the temperature interval between the dilatometric softening point and the onset of crystallisation wasn’t improved. Manuscript profile -
Open Access Article
3 - Production of porous TiC preform by the gel casting process in order to synthesize Ti3SiC2 MAX phase via infiltration of preform
حمزه فراتی راد hamidreza baharvandi mohamad maragheThe ternary compound Ti3SiC2 is a representative of materials that exhibit both metals and ceramics characteristics. Similar to metals, this compound is electrical and thermal conductive material, not susceptible to thermal shock and shows plastic properties at high tem MoreThe ternary compound Ti3SiC2 is a representative of materials that exhibit both metals and ceramics characteristics. Similar to metals, this compound is electrical and thermal conductive material, not susceptible to thermal shock and shows plastic properties at high temperature. When considering as a ceramic, it is elastically rigid, lightweight, creep and fatigue resistant and maintains their strengths to high temperatures. In this paper, T3SiC2 bulks have been synthesized by infiltrating Si liquid into porous TiC preforms. High-purity TiC and Si powders with molar ratios of 3TiC:(1 + x)Si (where x = 0.30, 0.50, 1.00) were used as starting powders. Silicon pellets were placed at the top of the precursor pellets as a liquid source. The phase formation and microstructure were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS) system. The results demonstrated that the 50 percent extra silicon results to formation of Ti3SiC2 with 92 wt.% purity. The conditions are favorable for the formation of the SiC secondary phase with increasing the amount of extra silicon to 100 percent. Also, an increase in the amount of extra silicon leads to the formation of Ti3SiC2 with the columnar morphology. Manuscript profile -
Open Access Article
4 - Synthesis and Characterizatin of Polyvinyl Alcohol/Aloe Vera Hydrogel Film by Solvent Casting Method for Wound Dressing Applications
محبوبه محمودی مونا حاجیان رعنا ایمانیIn this study, we have tried to make hydrogel films by polyvinyl alcohol and Aloe vera which used in treat wounds. The films were prepared by solvent casting method with different concentration of aloe vera include 20, 30 and 50%. Some properties of samples such as wate MoreIn this study, we have tried to make hydrogel films by polyvinyl alcohol and Aloe vera which used in treat wounds. The films were prepared by solvent casting method with different concentration of aloe vera include 20, 30 and 50%. Some properties of samples such as water absorption, degradation rate, water vapour transmission rate and mechanical properties were examined. Also, Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) test were carried out in order to identify the bonds and morphological assessment in the samples, respectively. The results showed that with increasing of aloe vera concentration to 30% (PA30), water absorption rate, degradation rate and mechanical properties are increased. In according to SEM investigations, we found with aloe vera increasing, the porosity on surface of samples was increased. In the other hand, water vapour transmission rate have direct comparison with percentage of aloe vera concentration. Finally, cell cytotoxicity and morphology fibroblast cells (L929) attached on the samples surface evaluated by in vitro assay. The results showed that cells proliferated in greater numbers on the PA30 sample compared to other samples. Therefore, our results indicated that polyvinyl alcohol/Aloe vera hydrogel films are a good choice for use in wound dressing. Manuscript profile -
Open Access Article
5 - The effect of homogenization on the microstructure and mechanical properties of transient liquid phase bonding between Inconel 718 and Inconel 600
ali khorram Akbar Davoodi Jamaloei Abed عابدIn this paper, the effect of homogenization on the microstructure and mechanical properties of transient liquid phase bonding between Inconel 718 and Inconel 600 using BNi-2 interlayer was investigated. The homogenization was performed on the bonded samples at 1050° MoreIn this paper, the effect of homogenization on the microstructure and mechanical properties of transient liquid phase bonding between Inconel 718 and Inconel 600 using BNi-2 interlayer was investigated. The homogenization was performed on the bonded samples at 1050°C for 45 min which have not any eutectic compounds. The homogenization was done at 1080°C for 6 hr and 12 hr and 1180°C for 1 hr,2 hr, and 3 hr. The results indicated that at the temperature of 1080°C for 12 hr, compounds of DAZ on Inconel 718 side were almost completely vanished. On the other hand, the homogenization was completed at 1180°C for 3 hr and any boride compounds was not observed in the DAZ of Inconel 718 and Inconel 600 alloys. When homogenization was complete, the hardness value of DAZ was decreased and this value equated to the hardness value of base metals. The results of bonding shear strength showed that the joint strength was significantly increased with elimination of the diffusion effected zones. Manuscript profile -
Open Access Article
6 - Effect of Shoulder Surface Angle of Tool on Joint Properties in Friction Stir Welding of 5052 Aluminium Alloy
فرهاد غرویFriction stir lap welding of 5052 aluminum alloy was performed in the present research, and lap joints were fabricated by rotational speed of 1450 rpm and welding speed of 63 mm/min. Three tools with different shoulder surface angle (i.e. 0, 5, and 10 degrees) were desi MoreFriction stir lap welding of 5052 aluminum alloy was performed in the present research, and lap joints were fabricated by rotational speed of 1450 rpm and welding speed of 63 mm/min. Three tools with different shoulder surface angle (i.e. 0, 5, and 10 degrees) were designed and used. The effect of shoulder surface angle on joint properties was studied by optical microscopy and tensile-shear test. The results showed that only at angle of shoulder surface of zero-degree a continuous channel-like void was formed in the advancing side near the nugget zone and extended along the welding direction. The lap joints with the highest fracture strength has the smallest hook size, and is fractured at fraying surface rather than in the hook defect during tensile-shear test. Hook size and effective plate thickness (EPT) decreased from 4.5 to 2 and 2.25 to 1, respectively, as the angle of shoulder surface increased while the highest tensile-shear properties were obtained around 4650 N/mm at angle of shoulder surface of 10 degrees. Manuscript profile -
Open Access Article
7 - Optimization of HVOF thermal spraying parameters to improve the oxidation resistance of MCrAlY coating using Response
mostafa tahariIn this research, effects of different coating process parameters on the final properties of thermal spray coatings obtained from HVOF method are investigated. For this aim, five different levels are considered for four effective parameters (Fuel injection rate, oxygen MoreIn this research, effects of different coating process parameters on the final properties of thermal spray coatings obtained from HVOF method are investigated. For this aim, five different levels are considered for four effective parameters (Fuel injection rate, oxygen injection rate, powder injection rate and spray distance) on HVOF process by response surface method (RSM) and minimum porosity and minimum oxidation layer thickness are considered as the responses. To investigate the microstructure of coatings, Thermal Grown Oxide (TGO) thickness and porosity, a Scanning Electron Microscopy (SEM) and image analysis method are applied. Oxidation test has done at1100ºC for 50 hours on coated samples. Results show that (oxygen injection rate and powder injection rate), (fuel injection rate and powder injection rate), (powder injection rate and spray distance) have a reaction on each other in the TGO thickness value. Also, (oxygen injection rate and powderinjectionrate), (fuel injection rate and powder injection rate) have a little reaction on the porosity against the other parameters which haven’t any effect on it. Investigation of the coated sample with optimized parameters reveals that porosity of the coating is about 0.5% and TGO thickness is about 5.3 micrometer. Manuscript profile -
Open Access Article
8 - Dissimilar welding of Incoloy 825 to AISI 316L austenitic stainless steel and evaluation of Microstructure and Mechanical properties
مهدی باباجانی مرتضی شمعانیان مسعود کثیریIn the present study, dissimilar joints welding of Incoloy 825 superalloy / 316L austenitic stainless steel by gas tungsten arc welding (GTAW) were investigated. In Inconel 625 weldment, dendretic microstructure was seen where cell-dendretic microstructure was found in MoreIn the present study, dissimilar joints welding of Incoloy 825 superalloy / 316L austenitic stainless steel by gas tungsten arc welding (GTAW) were investigated. In Inconel 625 weldment, dendretic microstructure was seen where cell-dendretic microstructure was found in base metal. There was no solidification crack in structure. In weldment/base metal interface, grain growth was seen in all of them except in 316L base metal/weldment 308L.Improved mechanical properties of weldment were attained by using of Inconel 625 welding wire. Manuscript profile -
Open Access Article
9 - A Study on Effect of Processing Parameters on Electrical Conduction and Micro-hardness of Nano-crystalline Cu-5%at Ta Alloy.
Roohollah Rahmanifard mohsen asadi asadabad سید میثم جاویدانAt the present study, the mechanical alloying method was used to produce the nanocrystalline Cu-5Ta alloy. In order to achieve a specimen with desirable properties, effects of size of milling ball, atmosphere and temperature of sintering were investigated on crystalline MoreAt the present study, the mechanical alloying method was used to produce the nanocrystalline Cu-5Ta alloy. In order to achieve a specimen with desirable properties, effects of size of milling ball, atmosphere and temperature of sintering were investigated on crystalline structure, electrical conduction and microhardness of specimen. The microstructural studies indicated that a finer crystallite size was attained when the complex size of milling balls being composed of 10 and 5 millimeters was applied rather than simple one of 10 millimeters. After milling, cold press and subsequent sintering were done under different atmospheres such as nitrogen, argon and vacuum at temperature of 550C. The sintered specimen under vacuum showed the better properties compared to the others. The further evaluations on specimen properties was conducted by sintering at temperatures of 700 and 850C under vacuum. The results indicated that with increasing the sintering temperature, electrical conduction and microhardness increase. Overall, the specimen milled by the complex ball size and sintered at temperature of 850C under vacuum experienced a electrical condition of 15.7% IACS and microhardness of 196.2 HV which was the best conditions to produce Cu5Ta. Manuscript profile -
Open Access Article
10 - Repair of Structural Steel Surface Groove by Using Spray Welding and Diffusion Welding Methods
سید ابراهیم وحدت یونس رحیمی پدرام کیهانیTo improve mechanical properties and increasing useful life of metal parts, different methods of welding are used for repairing surface crack of metal parts. In this research, performance of flame welding by spraying pure iron powder and diffusion welding of pure iron p MoreTo improve mechanical properties and increasing useful life of metal parts, different methods of welding are used for repairing surface crack of metal parts. In this research, performance of flame welding by spraying pure iron powder and diffusion welding of pure iron powder through magnetic induction evaluated for repairing surface cracks of structural steel. First, eight specimens prepared including two control specimen and other six specimens grooved specimens in depth of 1mm and in length of 12.5mm and groove width in the sizes of 0.5, 0.75 and 1mm. then, two methods of repairing had done. Results showed that after repairing surface groove by using flame welding method and diffusion welding method, tensile strength of the repaired specimens reached to the tensile strength of control specimen with the margin of 2.5% and 7.5%, respectively. Therefore, flame welding method was safer than diffusion welding method for repairing surface groove of structural steel by using pure iron powder. Manuscript profile
-
The rights to this website are owned by the Raimag Press Management System.
Copyright © 2021-2024