Author
Khaled Youssef
Other affiliations: Ain Shams University, Suez Canal University, Université du Québec ...read more
Bio: Khaled Youssef is an academic researcher from Qatar University. The author has contributed to research in topics: Nanocrystalline material & Materials science. The author has an hindex of 21, co-authored 84 publications receiving 2585 citations. Previous affiliations of Khaled Youssef include Ain Shams University & Suez Canal University.
Papers published on a yearly basis
Papers
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TL;DR: A low-density, nanocrystalline high-entropy alloy, Al20Li20Mg10Sc20Ti30 was produced by mechanical alloying as discussed by the authors, which formed a single phase fcc structure during ball milling and transformed to single phase hcp upon annealing.
Abstract: A low-density, nanocrystalline high-entropy alloy, Al20Li20Mg10Sc20Ti30 was produced by mechanical alloying. It formed a single-phase fcc structure during ball milling and transformed to single-phase hcp upon annealing. The alloy has an estimated strength-to-weight ratio that is significantly higher than other nanocrystalline alloys and is comparable to ceramics. High hardness is retained after annealing.
448 citations
TL;DR: In this article, a ball milling-based in situ consolidation technique was used to produce fully dense nanocrystalline Cu samples centimeters in lateral dimensions and about one millimeter in thickness.
435 citations
TL;DR: In this paper, the authors synthesized artifact-free bulk nanocrystalline copper samples with a narrow grain size distribution (mean grain size of 23nm) that exhibited tensile yield strength about 11 times higher than that of conventional coarse-grained copper, while retaining a 14% uniform tensile elongation.
Abstract: We have synthesized artifact-free bulk nanocrystalline copper samples with a narrow grain size distribution (mean grain size of 23nm) that exhibited tensile yield strength about 11 times higher than that of conventional coarse-grained copper, while retaining a 14% uniform tensile elongation. In situ dynamic straining transmission electron microscope observations of the nanocrystalline copper are also reported, which showed individual dislocation motion and dislocation pile-ups. This suggests a dislocation-controlled deformation mechanism that allows for the high strain hardening observed. Trapped dislocations are observed in the individual nanograins.
329 citations
TL;DR: In this article, a bulk nanocrystalline Al-5%Mg alloy was synthesized by an in situ consolidation mechanical alloying technique, which has four times the strength of a conventional Al-5083 alloy along with good ductility (8.5% elongation).
267 citations
TL;DR: In this paper, a unique way of using mechanical milling/in situ consolidation at both liquid-nitrogen and room temperature to produce artifact-free nanocrystalline Cu(23nm) with a narrow grain size distribution was reported.
Abstract: We report a unique way of using mechanical milling/in situ consolidation at both liquid-nitrogen and room temperature to produce artifact-free nanocrystalline Cu(23nm) with a narrow grain size distribution. This nanocrystalline Cu exhibits an extraordinarily high yield strength (770MPa), as predicted from a Hall–Petch extrapolation, along with good ductility (comparable with ∼30% uniform tensile elongation). Possible factors leading to this excellent optimization of strength and ductility are discussed.
169 citations
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TL;DR: High entropy alloys (HEAs) are barely 12 years old as discussed by the authors, and the field has stimulated new ideas and inspired the exploration of the vast composition space offered by multi-principal element alloys.
4,693 citations
TL;DR: The maximum strength of nanotwinned copper samples with different twin thicknesses is investigated, finding that the strength increases with decreasing twin thickness, reaching a maximum at 15 nanometers, followed by a softening at smaller values that is accompanied by enhanced strain hardening and tensile ductility.
Abstract: [Lu, L.; Chen, X.; Lu, K.] Chinese Acad Sci, Inst Met Res, Shenyang Natl Lab Mat Sci, Shenyang 110016, Peoples R China. [Huang, X.] Tech Univ Denmark, Riso Natl Lab Sustainable Energy, Ctr Fundamental Res Met Struct Four Dimens, Dept Mat Res, DK-4000 Roskilde, Denmark.;Lu, L (reprint author), Chinese Acad Sci, Inst Met Res, Shenyang Natl Lab Mat Sci, Shenyang 110016, Peoples R China;llu@imr.ac.cn
1,602 citations
TL;DR: In this paper, the authors provide an overview of metal-based material classes whose properties as a function of external size have been investigated and provide a critical discussion on the combined effects of intrinsic and extrinsic sizes on the material deformation behavior.
1,515 citations
TL;DR: In this paper, a critical review of the recent studies aiming to address the fundamental issues related to phase formation in high-entropy alloys is provided, and novel properties of HEAs are also discussed, such as their excellent specific strength, superior mechanical performance at high temperatures, exceptional ductility and fracture toughness at cryogenic temperatures, superparamagnetism and superconductivity.
1,494 citations