اسم المؤلف:
علي حسين صالح
اسم المشرف:
قاصد عبد الستار صالح الجنابي
المستخلص:
Spinel - Aluminum composites are drawing greater attention due to their low density, excellent physical, mechanical and refractory properties. This work aims to study the preparing one of the most current conventional technique and sintering behavior of Spinel - Al composite through characterization of the physical, mechanical properties as well as XRD and microstructure of the synthesis Spinel - Al composite specimens.Magnesia (MgO) and alumina (Al2O3) were used as starting materials to prepare stoichiometric magnesium aluminate spinel (MA) via single stage firing process (solid state reaction).Spinel (reinforced material) which prepared at sintering temperatures 12000C and 14000C for 2h soaking time was added in different weight percentage, i.e. 2,4,6,8 wt.% to the aluminum (matrix material) for synthesis Spinel - Al composites in a temperature range of 450 - 6500C via solid state reaction (SSR). The sintering parameters, XRD, microstructure, mechanical and thermal properties of the Spinel - Al composite products were investigated as well as the influence of each of the synthesized spinel contents and sintering temperature on sintering behavior of the composite products were also discussed. The results show that the better sintered density, water absorption, compressive strength, and thermal conductivity of the composite products obtained at low amount addition of spinel fired at 1200 and 14000C was 2wt.% and at 6500C.Also, studying of X - ray diffraction (XRD) for prepared spinel - aluminum composite specimens showed that the composites has many crystalline orientations (38.70, 44.970, 65.30 and 60.190), (390, 45.20, 65.620 and 60.330), (38.90, 45.150, 65.470, and 60.40) and (38.850, 45.260, 65.60 and 60.40) corresponding to (111), (200), (220) and (333) for 2,4,6,8wt% of spinel respectively.The studying of the morphology of spinel - aluminum composite specimens reveal that average grain size of reaches about 6.03, 6.17, 6.22, 6.3 (μm) for 2, 4, 6, 8 wt.% of MgAl2O4 fired at 12000C respectively, whereas their average grain size reaches about 7.18, 7.57, 7.9, 8.48 (μm) for the same spinel content fired at 14000C respectively.
