Muhammad Rashad

Development of magnesium-graphene nanoplatelets composite

In recent years, graphene has attracted a great research interest in all fields of sciences due to its unique properties. Its excellent mechanical properties lead it to be used in nanocomposites for strength enhancement. In current work, a new magnesium-graphene nanoplatelets composite is fabricated for the first time using semi-powder metallurgy method. The effect of graphene nanoplatelets addition on the mechanical behaviour of pure magnesium under both tension and hardness is investigated. The results demonstrate that graphene nanoplatelets are distributed homogeneously in the magnesium matrix, therefore act as an effective reinforcing filler to prevent the deformation. Compared to monolithic magnesium, the magnesium/0.3 wt% graphene nanoplatelets composite exhibited improved elastic modulus, yield strength, ultimate tensile strength and Vickers hardness. The improvement in elastic modulus, yield strength (0.2%), ultimate tensile strength and Vickers hardness for magnesium/0.3 wt% graphene nanoplatelets composite relative to pure magnesium are up to +10.6%, +5%, +8% and +19.3%, respectively. In addition to tensile and hardness tests for the analysis of mechanical properties of as synthesized composite, scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction are used to investigate the surface morphology, elemental percentage composition and phase analysis, respectively.

Improved performance of a MnO2@PANI nanocomposite synthesized on 3D graphene as a binder free electrode for supercapacitors

In the current study, we have synthesized a binder free nickel foam graphene MnO2@PANI (MnO2@PANI/graphene) nanocomposite by simple hydrothermal method followed by in situ polymerization. The graphene grown on nickel foam is used as a 3D scaffold conducting substrate for binder free nanocomposite electrode synthesis. Morphological characterization of the nanocomposite reveals growth of the MnO2 intercalated PANI nanorods-like network. The electrochemical study demonstrates very interesting electrode activation phenomenon, i.e. increase in specific capacitance upto 1500 charge–discharge cycles. The activated MnO2@PANI/graphene nanocomposite exhibits a maximum specific capacitance of 1369 F g−1 at 3 A g−1 current density and excellent rate capability of more than 70% by varying current density from 3 A g−1 to 15 A g−1. The activated electrode displays good cyclic stability by retaining SC over 83% after 5000 cycles.

Influence of Sn addition on mechanical properties of gas tungsten arc welded AM60 Mg alloy sheets

Abstract The effects of Sn addition on the microstructure and mechanical properties of gas tungsten arc butt-welded Mg–6Al– 0.3Mn (AM60) (mass fraction, %) alloy sheets were investigated by optical microscopy, scanning electron microscopy, X-ray diffraction, transmission electron microscopy, and microhardness and tensile tests. The results indicate that both the average microhardness and joint efficiency of AM60 are improved by the addition of 1% Sn (mass fraction). The ultimate tensile strength of Mg–6Al–1Sn–0.3Mn (ATM610) reaches up to 96.8% of that of base material. Moreover, fracture occurs in the fusion zone of ATM610 instead of in the heat-affected zone of AM60 welded joint. The improvement in the properties is mainly attributed to the formation of Mg 2 Sn, which effectively obstructs the grain coarsening in the heat-affected zone, resulting in a relatively fine microstructure. The addition of 1% Sn improves the mechanical properties of AM60 welded joint.

Effect of bias voltage on compositional, mechanical and corrosion property of ZrNbAlN multilayer films by unbalanced magnetron sputtering

Abstract Nano-scaled ZrNbAlN films with different negative bias voltages ( V b ) were deposited on bronze substrate and Si (100) wafers by a reactive unbalanced magnetron sputtering technique. Composition and structure properties were characterized by X-ray photoelectron spectroscopy and X-ray diffraction. It is found that mole concentrations of Zr and Nb are affected by V b , which leads to the increase of binding energy of N 1s and Al 2p and decrease of binding energy of Zr 3d 5/2 and Nb 3d 5/2 . Surface morphologies evolution controlled by V b could be observed. Furthermore, X-ray diffraction patterns reveal that these films show a (111) preferred orientation. Moreover, mechanical property and corrosion behavior of ZrNbAlN films were characterized by nanoindentation test and corrosion test, respectively. A maximum value of 21.85 GPa at −70 V occurs in the ZrNbAlN- bronze system, which outperforms uncoated bronze. Corrosion experiments in 0.5 mol/L NaCl and 0.5 mol/L HCl solution show that corrosion potential and corrosion current are dependent on V b , and better anti-corrosion property could be obtained at −90 V.