In this work, yttrium oxide particles (powder) reinforced AL-Si matrix composites (Y2O3/Al-Si) and Chromium oxide particles reinforced AL-Si matrix composites (Cr2O3/AL-Si) were prepared by direct squeeze casting. The volume percentages of yttrium oxide used are (4, 8.1, 12.1, 16.1 vol %) and the volume percentages of the chromium oxide particles used are (3.1, 6.3, 9.4, 12.5 vol. %). The parameters affecting the preparation of Y2O3/Al-Si and Cr2O3/AL-Si composites by direct squeeze casting process were studied. The molten Al-Si alloy with yttrium oxide particles or with chromium oxide particles was stirred again using an electrical stirrer at speed 500 rpm and the molten alloy was poured into the squeeze die cavity. The pouring temperature that used for all castings is (700)˚C. The required squeeze pressure, 53 MPa, was then applied for 30 seconds at a delay time of 5. The die temp is (200˚C). The Y2O3/Al-Si composites and Cr2O3/Al-Si composites produced by squeeze casting have more microstructure refinement, higher hardness and lower wear rate than the unreinforced alloy.
Abstract
This work involves the manufacturing of MAX phase materials include V2AlC and Cr2AlC using powder metallurgy as a new class of materials which characterized by regular crystals in lattice. Corrosion behavior of these materials was investigated by Potentiostat to estimate corrosion resistance and compared with the most resistant material represented by SS 316L. The experiments were carried out in 0.01N of NaOH solution at four temperatures in the range of 30–60oC. Polarization resistance values which calculated by Stern-Geary equation indicated that the MAX phase materials more resistant than SS 316L. Also cyclic polarization tests confirme
... Show MoreThis study was established to investigate the correlation between the expression of matrix metalloproteinases (MMP-1) and the pathogenesis of osteoarthritis (OA). Blood samples were collected from 55 female patients with inflammatory OA and controls for estimation of serum (MMP-1) levels. In the current study, there is significant increase (p<0.001) in the mean of serum MMP-1 levels in osteoarthritis females (4027.73 ± 1345.28 pg/ml) than that in control females (798.76 ± 136.79 pg/ml). It was concluded that MMP-1 may be associated with the pathogenesis of osteoarthritis.
This study was included the isolation of four strains from two species of lactic acid bacteria which as Lactococcus lactis subsp. diacetylactis; Lactococcus lactis subsp. lactis; Leuconostoc mesenteroides subsp. mesenteroides and Leuconostoc mesenteroides subsp. cremoris, were isolated from locally fermented diary products. The isolated were identified by using morphological, cultural and biochemical tests. Their abilities to producing flavor compounds as each Diacetyl and Acetoin after cultured on MRS broth media and incubation at 30 °c for 24 hours. The results indicated that’s all strains were produced the acetoin significantly (P<0.05) more than diacetyl compound. The production of Lactococcus lactis subsp. diacetylactis from Diacety
... Show MoreThe roots of international relations: peace or war: A critical review A great debate has taken place about international relations between scholars concerning peace and War .The concept of root is matched with that of exception. And the importance of the research lies in the ensuing results in the report about the legitimacy of war and the space it holds, so if the origin of international relation is war .the obstacles against it are going to decrease .and if the origin lies in peace then the dimension of its legitimacy will narrow. key words: international relation –peace-war. Résumé : L’Origine des relations internationales : guerre ou paix : révisions critiques L’origine des relations internationales entre guerre et paix, a s
... Show MoreMetal oxide nanoparticles demonstrate uniqueness in various technical applications due to their suitable physiochemical properties. In particular, yttrium oxide nanoparticle(Y2O3NPs) is familiar for technical applications because of its higher dielectric constant and thermal stability. It is widely used as a host material for a variety of rare-earth dopants, biological imaging, and photodynamic therapies. In this investigation, yttrium oxide nanoparticles (Y2O3NPs) was used as an ecofriendly corrosion inhibitor through the use of scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FT-IR), UV-Visible spectroscopy, X-ray diffraction (XRD), and energy dispersive X-ray spe
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