Showing 7 results for Tavoosi
M. Tavoosi, S. Rizaneh, G. H. Borhani,
Volume 36, Issue 1 (Journal of Advanced Materials-Spring 2017)
Abstract
Investigating the effect of Al2O3-TiB2/Fe complex reinforcement (CCMR) on the mechanical properties of aluminum composites was the goal of this study. For this purpose, the Al2O3-TiB2/Fe reinforcement powders were synthesized during milling and subsequent annealing. Different volume percentages of the produced reinforcement powders (1.25, 2.5 and 5 vol.%) were added to aluminum matrix, milled for 10 h and then hot extruded. The structural phasic and mechanical investigations of the specimens were carried out using X-ray diffraction, scanning electron microscopy and tensile test. The results showed that the metallic component (Fe rich phase) in this new type of reinforcement stuck the ceramic parts (Al2O3-TiB2) to aluminium matrix, and has an importance role in the flexibility of the product. The best volume percentage of CCMR in aluminium matrix was about 2.5%. This nanocomposite had a combination of strength and ductility of about 500 MPa and 6%, respectively.
Dr M. Tavoosi, S. Arjmand,
Volume 37, Issue 1 (Journal of Advanced Materials-Spring 2018)
Abstract
In this study, the formation of the Al3Ti intermetallic compound at the junction interface of aluminum-titanium was investigated during deposition and annealing. The results illustrated that during the deposition process, one thin layer of Ti3Al2 intermetallic compound was created at the junction interface. During the annealing at 550 °C, this layer was transformed to the Al3Ti intermetallic phase and the layer growth occurred. By performing annealing at higher temperatures, the growth rate of Al3Ti intermetallic layer was increased; at the same time, the formation of Kirkendall cavities and coupling in the cavities and fragmentation of diffusional coupling from the junction with aluminum were observed
A. Baradaran, M. Tavoosi,
Volume 37, Issue 3 (Journal of Advanced Materials-Fall 2018)
Abstract
In the present study, the structural, optical and thermal behaviors of GeO2-PbO-CaO-SrO glasses were investigated to achieve the highest optical properties and thermal stability. Accordingly, different 50GeO2-(50-x)PbO-xCaO and 50GeO2-(50-x)PbO-xSrO (x=0, 10, 20) germanate glasses were prepared by the conventional melt and quench technique between two steel sheets. The produced samples were characterized using X-ray diffraction (XRD), differential thermal analysis (DTA), Fourier transform infrared (FTIR) and UV-Vis spectroscopy. Based on the obtained results, the addition of CaO to glass composition reduced the glass phase forming ability as well as optical and thermal behaviors of the prepared glasses. In contrast, the presence of SrO had no destructive effect on the optical properties of the prepared glasses; the highest values of glass transition (580 oC) and crystallization temperature (831 oC) were achieved in the sample containing 20 mole% of SrO.
S. Arjmand, M. Tavoosi,
Volume 39, Issue 3 (Journal of Advanced Materials-Fall 2020)
Abstract
The present work aims to modify surface properties of pure Ti by development of Ti-Al-N intermetallic composite coatings. In this regard, tungsten inert gas (TIG) cladding process was carried out using Al 1100 as filler rod with Ar and Ar+N2 as shielding gases. Phase and structure of the samples were investigated by X-ray diffraction (XRD) technique, optical microscopy (OM) and scanning electron microscopy (SEM). Hardness values and corrosion behavior of the obtained coatings were also compared using Vickers microhardness tester and potentiostat, respectively. The results showed that composite structure containing Al3Ti, Ti3Al2N2 and Ti3Al intermetallic compounds could be formed on the surface of pure Ti. Amounts of brittle phases and welding defects at the titanium-coating interface were least by welding under pure Ar shielding. Despite the increasing amount of structural defects such as porosity and non-uniformity under Ar+N2 shielding, the prepared coatings had higher hardness (more than 100 HV) and corrosion resistance (more than twice) compared with those obtained under Ar shielding.
Kh. Zamani, M. Tavoosi, A. Ghasemi ,
Volume 39, Issue 4 (Journal of Advanced Materials-Winter 2021)
Abstract
In this research, effect of B and Si addition on the structural and magnetic properties of AlCoCrMnNi high-entropy alloys was investigated. The structural and magnetic properties of AlCoCrMnNiX(X= B, Si) alloys were studied by X-ray diffractometer (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and vibrating sample magnetometer (VSM). First, the constituent components of the AlCoCrMnNiX (X=B, Si) alloys were mixed for 10 hours. XRD analysis revealed that the solid solution was not formed by mixing. The alloys were then annealed at 900 ˚C for 10 hours. XRD results revealed formation of a solid solution with BCC structure in AlCoCrMnNi and AlCoCrMnNiB alloys. For AlCoCrMnNiSi and AlCoCrMnNiSiB alloys, Ni2Si and Cr2Si3 intermetallics were formed in addition to the solid solution with BCC structure. VSM results suggested that while forming the solid solution for AlCoCrMnNi alloy, soft magnetic properties improved so that magnetic saturation and coercivity increased from 40.22 to 64.46 emu/g, and from 180.143 to 14.09 Oe, respectively.
H. R. Karimi, H. Mansouri, M. R. Loghman Estarki, M. Tavoosi , H. Jamali,
Volume 40, Issue 1 (Journal of Advanced Materials-Spring 2021)
Abstract
This study aimed to compare the phase changes and morphology of yttria-stabilized zirconium oxide powders (YSZ) synthesized by co-precipitation and molten salt methods. Ammonia precipitating agent was used for the synthesis of YSZ powder by co-precipitation method and a mixture of sodium carbonate and potassium carbonate salts was used as a molten salt in the molten salt method. Samples were characterized by X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared Spectroscopy (FTIR), Thermal Gravimetric Analysis (TGA), and Differential Scanning Calorimetry (DSC) analysis. The results showed that only the sample prepared with zirconium oxychloride and yttrium nitrate by co-precipitation method had a single phase of yttria-stabilized zirconium oxide with tetragonal crystal lattice and particle size distribution in the range of 30 to 55 nm. The powder synthesized by the molten salt method contained a mixture of zirconia with monoclinic crystal lattice and yttria stabilized zirconia with tetragonal crystal lattice and particle size of 200 nm.
S. Sarafrazian, M. Tavoosi, A. Ghasemi ,
Volume 40, Issue 2 (Journal of Advanced Materials-Summer 2021)
Abstract
The aim of this study was optimization of the annealing process in melt spun Nd2Fe14B intermetallic magnetic alloy. In this regard, the melt spinning process was done at wheel speed of 40 m.s-1. In order to achieving the desired microstructure, the as-spun ribbons were subsequently annealed at temperature range of 500 to 700 ºC for different periods of time. Structural and magnetic characterization of produced samples were performed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM). The results showed that the structure of as-spun ribbons at wheel speed of 40m.s-1 was composed of Fe-α, Nd2Fe14B and amorphous phases with the coercivity and saturation of magnetization in the range of 0.14 kOe and 120 emu/g, respectively. By annealing the produced ribbons and crystallization of the amorphous phase, the percentage of Fe-α and Nd2Fe14B was decreased and increased, respectively. The optimum annealing conditions for achieving the highest value of coercivity (about 9.2 kOe) was 600°C for 6h.
