Papers by Author: O. Almahmoud

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Authors: A. Dominguez, A. Ali, F. Orantes, N. Ula, Y. Li, J. Foyos, H. Garmestani, A. Tabei, K. Almahmoud, O. Almahmoud, O.S. Es-Said
Abstract: Ti-6Al-4V powder, produced by the hydride-dehydride (HDH) process, was hot isostatically pressed (HIP) into three bars. The 10 cm (4 in) diameter bars were hot worked (HW) to three different diameters: 5.1 cm (2 in) (75% reduction in area), 3.8 cm (1.5 in) (86% reduction in area), and 2.5 cm (1 in) (94% reduction in area). Three samples were machined out of each bar along the end, middle and transverse orientations. These samples were ground, polished, and etched. The microstructure of the samples was evaluated at 100X and 200X magnifications. The objective of this experiment was to examine the effect of deformation on the microstructure and properties of hot rolled titanium alloy bar product. Charpy impact samples were also machined out of each of the various diameter bars. Impact testing was used to quantify toughness by correlating the microstructure to the energy absorbed. The tensile properties of the hot bars were determined as well as the crystallographic texture. Scanning electron microscopy (SEM) was performed on the fractured surface of the Charpy impact samples.
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Authors: T. Shimabukuro, R. Daouk, J. Skupnjak, M. Nordman, M. Burrell, L. Sutanto, A. Abad, Hamid Garmestani, N. Ula, J. Foyos, K. Almahmoud, O. Almahmoud, O.S. Es-Said
Abstract: Three Ti-6Al-4V plate materials produced by powder metallurgy technique, included pre-alloyed hydride-dehydride (HDH) plate rolled to 75% reduction in thickness, and two blended elemental (BE) powder plates rolled to 75% and 87% reduction were evaluated. The objective of this study was to determine differences in microstructure and toughness between the pre-alloyed HDH and BE Ti-6Al-4V materials processed to the same product form. Heat treatments were performed below the beta transus temperature at 982, 871, 760, and 732°C (1800, 1600, 1400, and 1350°F) for 1, 2, and 4 hours in order to determine differences in heat treating response, and above the beta transus at 1076°C (1970°F) to determine the transformation temperature. The samples were evaluated by optical microscopy and scanning electron microscopy. Charpy impact testing was performed in order to determine differences in the energy absorbed during fracture. Pole figures (0002) of selected conditions were also performed in order to determine any differences in texture between the various conditions.
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