List of Articles Ali Saidi

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  1 - The Effect of sintering temperature on microstructure and hardness of milled WC- 20 wt.% equiatomic (Fe,Co) cemented carbides
  Minoo Karbasi Maryam Karbasi Ali Saidi Mohammad Hossein Fathi
  In this study, WC–20 wt.% equiatomic (Fe,Co) powder mixture was milled in a planetary ball mill. The effects of different milling time (15 min, 5h, 10h, and 25 h) and sintering temperatures on the microstructure and mechanical properties of this equi-Fe substitute More

  In this study, WC–20 wt.% equiatomic (Fe,Co) powder mixture was milled in a planetary ball mill. The effects of different milling time (15 min, 5h, 10h, and 25 h) and sintering temperatures on the microstructure and mechanical properties of this equi-Fe substituted cermet were investigated. The structural evolution and the crystallite size changes of the powders during milling were monitored by X-ray diffraction (XRD). Microstructure developments of the samples were examined using scanning electron microscope (SEM). The results showed that the crystalline size of WC and internal strain were 22 nm and about 1.1 % after 25 hours of milling, respectively. The hardness and the relative density of the WC-20wt.% (Fe,Co) composites consolidated by conventional sintering at different temperatures, ranging from 1150 to 1450 ˚C in hundreds, were investigated. The optimized sintering temperature was measured at 1350°C. At a constant sintering temperature, 1350°C, the highest relative density of 98.2% and hardness of 1281 (HV30) were obtained for the milling time of 25h. Manuscript profile
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  2 - Production and Characterization of Nano Crystalline Fe85Si10Ni5 Soft Magnetic Alloys by Mechanical Alloying
  Arash Dezhsetan Ali Saidi Reza Ebrahimi-Kahrizsangi
  Abstract There are various methods to produce iron based nano crystalline magnetic alloys. Among these methods, mechanical alloying is one of the most important. In this research, nano crystalline Fe85Si10Ni5 soft magnetic alloy was synthesized by mechanical alloying. More

  Abstract There are various methods to produce iron based nano crystalline magnetic alloys. Among these methods, mechanical alloying is one of the most important. In this research, nano crystalline Fe85Si10Ni5 soft magnetic alloy was synthesized by mechanical alloying. The effect of alloying time on phase constituents and magnetic properties of the produced powders was investigated, by X-ray diffraction (XRD) and alternating gradient force magnetometer (AGFM). The XRD results showed that alloy formation started after 2 hours of milling. Further milling resulted in the reduction of the grain size and lattice parameter. After 60 hours of milling, the grain size was reduced to 8 nm. AGFM results showed that magnetic saturation and coercivity depends on the alloying time. Increasing the alloying time, causes the increase of magnetic saturation and decrease of coercivity. Abstract There are various methods to produce iron based nano crystalline magnetic alloys. Among these methods, mechanical alloying is one of the most important. In this research, nano crystalline Fe85Si10Ni5 soft magnetic alloy was synthesized by mechanical alloying. The effect of alloying time on phase constituents and magnetic properties of the produced powders was investigated, by X-ray diffraction (XRD) and alternating gradient force magnetometer (AGFM). The XRD results showed that alloy formation started after 2 hours of milling. Further milling resulted in the reduction of the grain size and lattice parameter. After 60 hours of milling, the grain size was reduced to 8 nm. AGFM results showed that magnetic saturation and coercivity depends on the alloying time. Manuscript profile
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  3 - Sintering and Characterizations of WC-20wt.% (Fe,Co) Nano-Structured Powders Developed by Ball-Milling
  Minoo Karbasi Maryam Karbasi Ali Saidi Mohammad Hossein fathi
  The aim of the present work is to study the effects of the nanostructured WC-20 wt. % (Fe,Co) with different ratios of iron to cobalt on the microstructure and hardness of sintered samples. Furthermore, a sample with a cobalt binder under the same condition was produced More

  The aim of the present work is to study the effects of the nanostructured WC-20 wt. % (Fe,Co) with different ratios of iron to cobalt on the microstructure and hardness of sintered samples. Furthermore, a sample with a cobalt binder under the same condition was produced for the comparison purposes. The nanocomposite development, after different milling times, has been monitored by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). A homogenous distribution of nanostructured WC (crystallite size less than 30 nm) in the binder matrix was formed after 25 h milling. The hardness and the relative density of the WC-20wt. % (Fe,Co) composites consolidated by conventional sintering at 1350˚C were investigated. In sintered samples after 25 h milling, tungsten carbide grains have a uniform distribution with a lower grain size. Densification and hardness improved after 25 h milling and reached optimum levels for the 25 h milled powders with equal ratio of iron to cobalt. Manuscript profile
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  4 - Effect of Ni on Amorphization of Ti-Cu-Ni Ternary alloys Prepared by Mechanical alloying
  Masoud Ghadiri Ali Saidi
  Amorphous alloys has been taken into consideration because of their unique properties and are nominated as the future engineering materials. In this research, the effect of Ni and milling time on amorphization process and thermal stability of Ti50Cu50-xNix(x=10, 15, 25 More

  Amorphous alloys has been taken into consideration because of their unique properties and are nominated as the future engineering materials. In this research, the effect of Ni and milling time on amorphization process and thermal stability of Ti50Cu50-xNix(x=10, 15, 25 at%) alloy system were investigated. The evolution of amorphization during milling, thermal stability and subsequent heat treatment were evaluated by x-ray diffraction (XRD) and differential scanning calorimetry (DSC). The results showed that alloys reached to the highest content of amorphous phase in Ti50Cu40Ni10, Ti50Cu15Ni35 and Ti50Cu25Ni25 alloy compounds after 60, 40 and 10 hours respectively. Differential scanning calorimetry showed thermal stability of amorphous alloy, exhibiting a distinct glass transition and crystallization temperature and a wide supercooled liquid region for Ti50Cu25Ni25 powder alloy with a value about 45 k. Heating Ti50Cu25Ni25 amorphous alloy at 943 k for 10 min results in the formation of intermetallics such as CuTi and NiTi2 phases. In addition, mechanical properties of amorphous powders were studied by Vickers microhardness test. The alloy with 25 percent Ni showed The high value of hardness about 884 Hv after 40 hours milling. Manuscript profile
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  5 - Effects of Replacing Fluorine with Sodium and Titanium Oxides on Continuous Casting of Steel Mold Powders Lubrication
  Ahmadreza Arefpour Ahmad Monshi Ali Saidi
  Mold powders are used as raw materials in continuous casting of steel industry; Also they are mostly composed of aluminum, calcium, silica oxides, alkaline and earth-alkaline oxides along with carbon and fluor. Two of the most important duties of mold powders are the lu More

  Mold powders are used as raw materials in continuous casting of steel industry; Also they are mostly composed of aluminum, calcium, silica oxides, alkaline and earth-alkaline oxides along with carbon and fluor. Two of the most important duties of mold powders are the lubrication of the space between mold walls and steel shell, and heat transfer control between steel shell and the copper mold. Fluor is one of the most important constituents of mold powders and is employed to control viscosity in order to obtain favorable lubrication and solidification temperature control in order to control heat transfer. The fluor in the mold powder is added to it with the aid of some fluorided compounds like fluorine (CaF2). This study has used Fluorine to make a powder similar to the reference sample, with the use of portland cement clinker and fluorine. Moreover, groove viscometer studies have been conducted here to compare sample viscosities to the viscosity of the reference sample. In addition XRD as well as SEM analyses were conducted. As a result, crystalline phase of cuspidine was found in the glass matrix indicating that the chemical compound in sample 1 may be a suitable substitute, as compared to the reference sample, for the mold powder used in continuous casting steel industry. Manuscript profile
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  6 - Silicothermic production and characterization of FeSiNi/SiO2 Magnetic nanocompsite via mechanical alloying
  Ghazal Sharifian asl Ali Saidi
  In recent years, a lot of research has been done in the field of producing soft magnetic nano composites by means of mechanical alloying. These materials indicate more electrical resistance and permeability in comparison with soft magnetic composites (SMCs). In this res More

  In recent years, a lot of research has been done in the field of producing soft magnetic nano composites by means of mechanical alloying. These materials indicate more electrical resistance and permeability in comparison with soft magnetic composites (SMCs). In this research, reduction of silicothermal mixed powder (Nickel-oxide, Silicon and Iron) was carried out by mechanical alloying to form soft nano composites of FeSiNi/SiO2. Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) were used to detect physical characterization and finding the effect of milling time on micro structural properties. It is determined that initiation of forming the homogenous alloy was in 4 hour milling, increasing the time of milling to 40 hours caused decreasing grain size to 13 nm and formation of homogenous alloy. Magnetic properties of milled powder were studied by alternating gradient force magnetometer (AGFM) and it was observed that increasing milling time will cause improvement in soft magnetic properties (decreasing magnetic coercivity and increasing magnetic saturation). Manuscript profile