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minimum-surface-roughness
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Self-limited growth of large-area monolayer graphene films by low pressure chemical vapor deposition for graphene-based field effect transistors
, Article Ceramics International ; Volume 43, Issue 17 , 2017 , Pages 15010-15017 ; 02728842 (ISSN) ; Razzaghi, Z ; Ghadiani, B ; Tamizifar, M ; Mohmmadi, M. H ; Simchi, A ; Sharif University of Technology
Abstract
During the last decade, fabrication of high-quality graphene films by chemical vapor deposition (CVD) for nanoelectronics and optoelectronic applications has attracted increasing attention. However, processing of large-area monolayer and defect-free graphene films is still challenging. In this work, we have studied the effect of processing conditions on the self-limited growth of graphene monolayers on copper foils during low pressure CVD both experimentally and theoretically based on thermokinetics and kinetics of Langmuir adsorption. The effect of copper pre-treatment, growth time, and carbon potential of the atmosphere (indicated by the methane-to-hydrogen gas ratio, r) on the quality of...
Parametric modelling and multi-objective optimization of electro discharge machining process parameters for sustainable production
, Article Energies ; Volume 13, Issue 1 , 2019 ; 19961073 (ISSN) ; Sarfraz, S ; Ahmad, W ; Shehab, E ; Salonitis, K ; Sharif University of Technology
MDPI AG
2019
Abstract
Electro Discharge Machining (EDM) can be an element of a sustainable manufacturing system. In the present study, the sustainability implications of EDM of special-purpose steels are investigated. The machining quality (minimum surface roughness), productivity (material removal rate) improvement and cost (electrode wear rate) minimization are considered. The influence and correlation of the three most important machining parameters including pulse on time, current and pulse off time have been investigated on sustainable production. Empirical models have been established based on response surface methodology for material removal rate, electrode wear rate and surface roughness. The...
Enhancement in microstructural and mechanical performance of AA7075 aluminum alloy via severe shot peening and ultrasonic nanocrystal surface modification
, Article Applied Surface Science ; Volume 528 , 2020 ; Karademir, I ; Husem, F ; Maleki, E ; Karimbaev, R ; Amanov, A ; Unal, O ; Sharif University of Technology
Elsevier B.V
2020
Abstract
In this experimental study, AA7075 aluminum alloy was subjected to pure severe shot peening (SSP), pure ultrasonic nanocrystalline surface modification (UNSM) and the combination of these two treatments. The treated specimens were analyzed with detailed microstructure analysis, micro-hardness, surface roughness, XRD investigations and wear-friction tests. The results demonstrated that UNSM exhibited fine surface finish and provided minimum surface roughness with the Ra value of 0.8 µm. Moreover, UNSM played an important role in the reduction of Ra as a secondary treatment. Electron back scatter diffraction (EBSD) analysis, full width at half maximum (FWHM) evaluations and compressive...