Papers by Author: O.S. Es-Said

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Authors: C. Parrish, J. Barba, H.M. Oh, J. Peraza, J. Foyos, E.W. Lee, O.S. Es-Said
Authors: D. Aliya, L.W. Walker, E. Montz, S. Pastor, A. Abad, F.A. Hashim, A. Abdul-Latif, A.O. Al-Roubaiy, Y.S. Oh, H. Garmestani, N. Ula, O.S. Es-Said
Abstract: This study investigated actively brazing Alumina-to-Alumina with Ag-Cu-Ti as the filler metal system and Alumina-to-Copper with Cu-Ti-Co as the filler-metal system. The research was conducted on four samples, two of which were alumina brazed to alumina (Samples 1 & 2), and the other two were alumina brazed to copper (Samples 3 & 4). The filler metal composition for each sample was as follows: Sample 1 consisted of Cu-96%, and Ti-4%; Sample 2 consisted of Ag-70%, Cu-26%, and Ti-4%; Sample 3 consisted of Cu-85%, Ti-10%, and Co-5%; and Sample 4 consisted of Cu-55%, Ti-40%, and Co-5%. The phase transformations between the filler and base metal of each brazed joint were studied using EDS, SEM, optical microscopy, and X-ray diffraction.
Authors: M. Trinca, A. Avalino, Hamid Garmestani, J. Foyos, E.W. Lee, O.S. Es-Said
Authors: E.W. Lee, O.S. Es-Said
Abstract: Aluminum alloys 6061-T6, 7075-T6 and 7249-T76 were subjected to several combinations of solution treatments, quenching media, and age hardening treatments to correlate their mechanical tensile properties to hardness and conductivity measurements. Additionally, the 6061-T6 and 7075- T6 alloys were thermally exposed to several temperatures to simulate heat damage effects. The thermal exposure was correlated to the tensile properties and hardness and conductivity measurements.
Authors: A. Al Sumait, C. Delgado, F. Aldhabib, X. Sun, F. Alzubi, K. Tovalin, A. Cheng, R.M. Campo, Y.J. Li, B. Ramsey, L. Zeng, O.S. Es-Said
Abstract: The objective of the study was to optimize the strength and ductility values of the 4330M steel. Optimization was conducted through different types of heat treatments. Tensile testing, hardness testing, optical microscopy, and Scanning Electron Microscopy (SEM) were used to evaluate the mechanical properties and microstructure of the as-received and the heat treated samples. The alloy was provided from two vendors; vendor H and vendor S. Results showed that by increasing the tempering temperatures, strength values decreases, while ductility values remain unchanged. Vendor H samples had higher strength values and much finer grain structure which was revealed only at 5000x magnification.
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.
Authors: E. Acosta, O. Garcia, A. Dakessian, K. Aung Ra, J. Torroledo, A. Tsang, M. Hahn, J. Foyos, J. Ogren, O.S. Es-Said
Authors: K. Escobar, B. Gonzalez, J.L. Ortiz, P.N. Nguyen, D. Bowden, J. Foyos, J. Ogren, E.W. Lee, O.S. Es-Said
Authors: P. Fleck, D. Calleros, M. Madsen, T. Trinh, D. Hoang, J. Foyos, E.W. Lee, O.S. Es-Said
Authors: Abdulhamid Al-Abduljabbar, O.S. Es-Said
Abstract: The purpose of this study is to characterize the effects of heat damage on the electrical conductivity and static mechanical properties of aluminum alloys. The data resulting from the experiments of thermal exposure of several aluminum alloys are used to model the relations that describe the dependence of the electrical conductivity and hardness on the two main variables of these experiments: the temperature and the time of exposure. The dependence of yield strength and ultimate tensile strength on hardness values is characterized. For each case, different materials (alloys) exhibit similar general trends although there are different coefficients for each material to satisfy the general relation.
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