Iranian Journal of Materials Science and Engineering

• Effects of natural aging treatment on mechanical, microstructural and forming properties of Al 2024 aluminum alloy sheets were investigated experimentally.
• To simulate the natural aging condition, forming limit diagrams were determined after specific times (e.g., 0.5, 1.5, 4 and 24 hours).
• The Variations in micro-hardness, yield strength, ultimate tensile strength and elongation at break were observed with changing the aging time.
• The scanning electron microscope (SEM) investigations illustrated that density and size of precipitates were changed with aging time.
• Results showed by changing the aging time up to 4hr the properties had the majority of their variations and from 4hr to 24hr, the variations were changed slower.

 
 

• Nano composite GPE based on PAN as polymer host and Sodium fluoride (NaF) as dopant salt and Al₂O₃ as nano filler in the form of thin films through solution casting technique consuming N,N-dimethyl formamide (DMF) as a common solvent.
• NCGPE films have been prepared by solution casting technique and characterized.
• The salt complexation and nano filler with the polymer is proved by XRD and FTIR studies.
• Inter planar spacing is also verified theoretically and experimentally. It is clear from SEM that with increasing of salt and nano filler concentration the surface of the films roughness has been decreased and phase segregation is revealed with cylindrical shape.
• The surface morphology of the samples were characterized by SEM. While increase in conductivity with increasing concentration of nano filler and temperature due to increasing of the amorphous nature. With 1-4 wt% Nano Composite compared filler free electrolyte. The ionic transference number data indicate that the conduction in these NCGPE is predominantly due to ions rather than electrons. Using PAN: NaF (70:30) gel polymer electrolyte system solid–state battery (Na/PAN: NaF (70:30)
• +EC+DMF/ (I₂+C+Electrolyte)) has been fabricated and their discharge profiles were studied and these results were found to be comparable with current results.

 
 

• With increasing Ti content from 1wt% in sample Fe-B-C-Ti-1  to 2.4wt.% in sample Fe-B-C-Ti-3, the microstructure changed from TiC + layered eutectic α-Fe₂B to primary Fe₂B + TiC + TiB₂ + vermicular eutectic α-Fe₂₃(B,C)₆
• With increasing Boron content, no detrimental FeB phase and cracks formed around Fe₂B.
• At applied loads, Fe-B-C-Ti-3 and Fe-B-C-Ti-1 have the lowest and highest wear rate, respectively.
• The higher wear resistance of Fe-B-C-Ti-3 is related to the higher levels of B and Ti, which has increased hardness.

• PTh-Co nanocomposites were produced.
• Investigated for structure, morphology and dielectric properties.
• AC conductivity estimated and analyzed.
• Electrical insulating effect observed in composites with increasing cobalt nps.
• Dielectric relaxation times were determined.

• The effect of different injection parameters on volumetric shrinkage was studied.
• Semi-crystalline polymers had noteworthy higher shrinkage compared to amorphous.
• The shrinkages along and across the flow directions were calculated.
• Cooling time was the most effective parameter on shrinkage of PE and PC.
• The optimal conditions for minimization of shrinkages of PE and PC were achieved.

1. Interfacial layers of Al/Brass, from the solid brass side to Al side, are analysed.
2. The effect of rotational speed and solid/melt fraction on the formation of reaction layer are studied.
3. Gas entrapment and surface aluminium oxide film entrainment are shown and the possible reasons are discussed.
4. Possible ways of reduction of the reaction layer seems to be higher rotational speed and precise S/M fraction.

• Mechanical properties of Al–Zn–Mg–Cu cast alloys was investigated.
• Al–30Er is an effective master alloy in reducing the grain size.
• The increase in the tensile properties by the addition of grain refiner is due to fine distribution of the secondary phases.
• Grain refinement by the addition of 1 wt.%  Er, T6 heat treatment and extrusion process improves the strength and elongation values.
• T6 heat treatment and extrusion process make about 167% enhancement in tensile strength.
• Fracture surfaces of the specimens showed an intergranular fracture in unrefined allo

The lowest value of K_∞ is obtained with   level -1 for Ep, tp, Ga and level 1 for ta.
Considering constraint related to the stiffness ratio, . The best selection appeared to be the level 0 for both parameters, which correspond to Ep=145 GPa and tp=1mm.
Considering all design constraints the final optimum design is obtained with the level 0 for Ep and tp, the level-1 for Ga and the level 1for ta.