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Author

Walid Mohamed

Other affiliations: North Carolina State University
Bio: Walid Mohamed is an academic researcher from Argonne National Laboratory. The author has contributed to research in topics: Irradiation & Nanocrystalline material. The author has an hindex of 6, co-authored 21 publications receiving 104 citations. Previous affiliations of Walid Mohamed include North Carolina State University.

Papers
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Journal ArticleDOI
TL;DR: In this paper, the effect of material characteristics such as grain size, texture and testing conditions such as temperature and strain rate on the formability of a wrought Mg-2Zn-1Mn alloy was investigated.
Abstract: This study is focused on furthering our understanding of the different factors that influence the formability of Magnesium alloys. Towards this end, formability studies were undertaken on a wrought Mg-2Zn-1Mn (ZM21) alloy. In contrast to conventional formability studies, the impression testing method was adopted here to evaluate the formability parameter, B, at temperatures ranging from 298 to 473 K. The variation of B of ZM21 with temperature and its rather limited values were discussed in the light of different deformation mechanisms such as activation of twinning, slip, grain boundary sliding (GBS) and dynamic recrystallization (DRX). It was found that the material characteristics such as grain size, texture and testing conditions such as temperature and strain rate, were key determinants of the mechanism of plastic deformation. A by-product of this analysis was the observation of an interesting correlation between the Zener-Hollomon parameter, Z, and the ability of Mg alloys to undergo DRX.

20 citations

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TL;DR: The role of grain size on the developed microstructure and mechanical properties of neutron irradiated nanocrystalline copper was investigated by comparing the radiation response of material to the conventional micrograined counterpart, finding that grain growth in nc-copper is composed of both thermally-activated and irradiation-induced components.
Abstract: The role of grain size on the developed microstructure and mechanical properties of neutron irradiated nanocrystalline copper was investigated by comparing the radiation response of material to the conventional micrograined counterpart. Nanocrystalline (nc) and micrograined (MG) copper samples were subjected to a range of neutron exposure levels from 0.0034 to 2 dpa. At all damage levels, the response of MG-copper was governed by radiation hardening manifested by an increase in strength with accompanying ductility loss. Conversely, the response of nc-copper to neutron irradiation exhibited a dependence on the damage level. At low damage levels, grain growth was the primary response, with radiation hardening and embrittlement becoming the dominant responses with increasing damage levels. Annealing experiments revealed that grain growth in nc-copper is composed of both thermally-activated and irradiation-induced components. Tensile tests revealed minimal change in the source hardening component of the yield stress in MG-copper, while the source hardening component was found to decrease with increasing radiation exposure in nc-copper.

13 citations

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TL;DR: In this article, a combination of synchrotron x-ray and MeV/Nucleon ion irradiation is demonstrated on U-Mo fuels and a preliminary look at HT-9 steels is also presented.

12 citations

Journal ArticleDOI
TL;DR: In this article, the effect of fission fragment energy Xe ion irradiation on the lattice strain of a single crystal Molybdenum (Mo) was investigated with a depth resolution of 0.7μm.

12 citations

Journal ArticleDOI
TL;DR: In this article, a modified thermal atomic layer deposition (ALD) system was constructed to produce one micron thick zirconium nitride (ZrN) coating over spherical particulate of natural uranium-molybdenum (U-Mo) based fuel.

11 citations


Cited by
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01 May 1993
TL;DR: Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems.
Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

29,323 citations

Book
12 Jan 2015
TL;DR: College Physics Select one of the following Physics sequences: 10 Algebraand Trigonometry-based: PHSX 205N & PHSZ 206N College Physics I and College physics I Laboratory PHSx 207N &PHSX 208N College physics II and College Physics II Laboratory Calculus-based (strongly recommended): PHS X 215N & pHSX 216N Fund of Physics w/Calc I and Physics Laboratory I w/ Calc PHSXM 217N
Abstract: College Physics Select one of the following Physics sequences: 10 Algebraand Trigonometry-based: PHSX 205N & PHSX 206N College Physics I and College Physics I Laboratory PHSX 207N & PHSX 208N College Physics II and College Physics II Laboratory Calculus-based (strongly recommended): PHSX 215N & PHSX 216N Fund of Physics w/Calc I and Physics Laboratory I w/Calc PHSX 217N & PHSX 218N Fund of Physics w/Calc II and Physics Laboratory II w/Calc Total Hours 10

285 citations

Journal ArticleDOI
TL;DR: In this paper, the deformation and fracture behaviors of as-cast AZ31B Mg alloy were studied by uniaxial compression experiments and finite element simulations with wide ranges of temperature and strain rate.

83 citations

Journal ArticleDOI
TL;DR: The original version of this Article contained a typographical error in the spelling of the author Chae-Myeong Ha which was incorrectly given as Chae -Myung Ha, which has now been corrected.
Abstract: Scientific Reports 5: Article number: 16577; 10.1038/srep16577published online November122015; updated: January272016 The original version of this Article contained a typographical error in the spelling of the author Chae-Myeong Ha which was incorrectly given as Chae-Myung Ha. This has now been corrected in the PDF and HTML versions of the Article.

44 citations

Journal ArticleDOI
TL;DR: In this article, the deformation behavior of particle reinforced magnesium matrix composite (PMMCs) is analyzed and the future development of PMMCs is suggested based on the current research progress.
Abstract: Particle reinforced magnesium matrix composite (PMMC) possesses the merits of high specific strength, high specific modulus, better dimensional stability, good wear resistance and lower production cost, which is thought as a promising material in the field of aerospace, automobile, electronic communication, etc. To eliminate the casting defect, the PMMC is usually experienced hot deformation process. The present paper mainly focuses on the deformation behavior of PMMCs. First, the development of PMMCs based on particle size is introduced. Then, the hot deformation technology and deformation mechanism of PMMCs at elevated temperature are given and analyzed, respectively. After reviewing the dynamic recrystallization and texture of PMMCs, its future development is suggested based on the current research progress.

42 citations