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In this study, various amounts of clay nanoparticles and titan nanoparticles (1, 3 and 5% wt.) were introduced into a vinyl ester resin matrix by high shear mixer. The influence of these nanoparticles on the mechanical properties (tensile strength, tensile modulus, flexural strength, flexural strength and fracture toughness) is investigated. To investigate the structure of nanocomposites, X-ray diffraction (XRD) and transmission electron microscopy (TEM) tests are done. The XRD test shows that the structure of clay-vinyl ester nanocomposites is exfoliated. The results of tensile, flexural and fracture toughness experiments show that clay is better than titan in the improvement of the mechanical properties. Clay- vinyl ester nanocomposite with 1% wt. of clay has the better mechanical properties than others samples.

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In this paper, the energy absorption capacity of A356 aluminum foam reinforced by SiC particles under impact loading was studied. The foam was manufactured by direct foaming of melts with blowing agent CaCO3. The drop-weight impact testing machine was designed and fabricated. The dynamic load-cell circuit was designed and mounted on the impactor. The impact test was carried out using a hemispherical indenter with a velocity of 6.70 m/s on the foam specimens, and the load-time history data was obtained. The results were compared with the results reported by a piezoelectric force sensor and validated. The obtained impact response of A356/SiCp composite foam is stable, which represents a suitable design of the machine and its reliable output. This is emphasized by comparison of material behavior with the results of other researchers. The response includes three stages: an initial linear behavior, a plateau of load and failure of the foam. In plateau region, the plastic deformations can be tolerated by the foam at nearly constant load. The end of plateau region and beginning of the failure region occur at the moment when the rate of energy absorbed by the foam is decreasing. The values of plateau load and absorbed energy estimated from load-cell are 1.62 kN and 22.04 J respectively, which has a relative error of 1.8% and 7.7% in comparison with piezoelectric sensor. The value and percent of absorbed energy were obtained as 6.07 J, 6.58 J, 9.39 J and 27.5%, 29.9%, 42.6% for elastic, plateau and failure regions respectively.

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In this paper, the effect of heat treatment on the impact behavior of A356 aluminum alloy foams reinforced by SiC particles was studied and new results was generated. The foam was manufactured by direct foaming of melts with blowing agent CaCO3. A number of foam specimens were processed by T6 aging treatment. The drop-weight impact test with a hemispherical striker tip and velocity of 6.70 m/s was carried out on five untreated foam specimens and five heat-treated foam specimens, and the load versus time history data was obtained. The obtained impact response of A356/SiCp composite foam includes three stages: an elastic region, a plateau of load region and complete failure region. In plateau region, the plastic deformations can be tolerated by the foam at nearly constant load. The small amounts of standard deviation and coefficient of variation (for different parameters) obtained from statistical analysis of experimental data indicates the reliance on the results for quantitative analysis of them. The measurements showed that heat treating of Al foam results in an increase of the plateau load level and energy absorption capacity of the foam with 48.1% and 40.3% increase respectively. The length of plateau region is also decreased due to heat treatment. Regarding the significant improvement of mechanical properties of the foam and increase of its impact strength, the heat treatment after foam casting can be considered as a suitable approach for various industrial applications of aluminum foam.