In-situ fabrication of metal matrix nano composites has various advantages such as the formation of clean particle-metal interface with strong bonding. In this study, three types of metal oxides powders (commercial TiO2, commercial ZnO, and recycled Pyrex) were used to inject into the pure aluminium melt to fabricate in-situ aluminium matrix nano composites via liquid-state stir casting at 850 °C followed by a hot rolling process. SEM and FESEM microstructural characterizations, as well as EDAX analysis, were used to show if in-situ reactions occurred between molten aluminium and metal oxides to form nano alumina particles as the reinforcement. Tensile and microhardness tests were also applied on the rolled nano composites to identify the effect of metal oxide type and amount on the mechanical properties. It was found that using recycled Pyrex crushed powders led to the formation of a uniform distribution of alumina nanoparticles, while fine-micron ZnO and especially TiO2 powders could not be uniformly distributed into the melt for complete reaction occurrence.

This investigation was undertaken to predict the mass gain (MG) of cobalt electroless deposition (ED) on ceramic SiC particles. Response surface methodology (RSM) based on a full factorial design with three ED parameters and 30 runs was used to conduct the experiments and to establish a mathematical model by means of Design-Expert software. Three ED parameters considered were pH, bath temperature and ceramic particle morphology. Analysis of variance was applied to validate the predicted model. The results of confirmation analysis by scanning electron microscopy (SEM) show that the developed models are reasonably accurate. The pH is the most effective parameter for the MG. Also, the highest mass gain is obtained for the lowest pH, highest bath temperatures and heat-treated SiC particles. In addition, the developed model shows that the optimal parameters to get a maximum value of mass gain are pH, bath temperature and ceramic particle state of 8, 70°C and heat treatment, respectively.

High-entropy alloys (HEAs) are among multi-component alloys with attractive microstructures and mechanical properties. In this study, molecular dynamics simulation was used to determine the tensile behaviour of glassy Al x CrCoFeCuNi HEAs from 300 • K to 1300 • K. For this purpose, this alloy with variations in chemical concentration of aluminum were heated and then cooled at a high cooling rate of 0.211 × 10 12 K/s. Results from radial distribution functions (RDF) and common neighbor analysis (CNA) indicated that no crystalline structures were formed for these glassy alloys. The deformation behaviour and mechanisms of the glassy alloys at room and high temperatures and various strain rates were investigated and reported. The tensile test results showed that the yield stress decreased markedly as temperature was increased for all the alloys. The alloys exhibited superplastic behaviour for all test conditions. More importantly, by increasing the molar ratio of aluminum from 0.5 to 3.0, the yield stress and elastic modulus decreased considerably. Also, the yield stress increased with increasing the strain rate for all samples with different aluminum concentrations. Free volume content of the alloys as well as shear banding were evaluated for these alloys to aid explanation of these results.

The microstructure of high-temperature metals such as Ti, Ni, and Cr can be modified using ceramic nanoparticles to form metal matrix nanocomposites (MMNCs). Such materials are generally prepared via powder metallurgy routes. In this study, 25 wt. % SiCnp and Al2O3np were separately ball-milled as a reinforcement of Ti, Cr, and Ni matrices to investigate their effects on the phase formation and morphology of the MMNCs. The XRD, SEM, and FESEM results indicated that the alumina-metal system could not be thermodynamically stable in a high-energy ball mill, while the SiC reinforcement could be retained and milled with the metals even after 24 hours. It was further observed that the distribution of nanoparticles was not affected by the type of metal, ceramic, and milling time. Finally, it was determined that the nanoparticles significantly reduced the average particle size of composite powders.

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