Ahmed M. Nabawy

In the present work, metallic foams of Al, Mg and an Al-SiC nanocomposite (MMNC) have been fabricated using a new manufacturing technique by employing melt infiltration assisted with an electromagnetic force. The aim of this investigation was to study and to develop a reliable manufacturing technique consisting of different types of metallic foams. In this technique, an electromagnetic force was used to assist the infiltration of Al-SiC slurry and of pure liquid metal into a leachable pattern of NaCl, thus providing perfect cellular structures with micro-sized porosities. A high frequency induction coil unit equipped with a vacuum chamber and a hydraulic press was used to manufacture the foam materials. Microstructures of the produced foam materials were explored by using Field Emission Scanning Electron Microscopy (FESEM). The mechanical behavior of the manufactured foams was investigated by applying compression testing. The results indicate a high applicability of the new technique in producing metallic foams of pure metals and of a metal matrix nanocomposite . The produced foam materials displayed isotropic cellular structures with excellent compressive behaviors. Microstructure measurements indicate that the average pore size and strut thickness that can be achieved are in the ranges of 100–500 μm and 50–100 μm, respectively. The produced foam of the Al-SiC nanocomposite material provided the highest strength of 50 MPa prior to the densification stage, which equates to 25 times, and 10 times higher than the strength levels that were obtained by Al, and Mg foams, respectively.

Al–TiC nanocomposite materials have been prepared by a new in situ synthesizing technique. A mixture of aluminum, titanium, and graphite has been prepared using ball milling technique and then melted in a high frequency induction heat furnace (HFIHF) at different sintering temperatures, namely 900, 1100, and 1300 °C. The effect of sintering temperature on the corrosion of the Al–TiC composite in 3.5% NaCl solutions was investigated using cyclic potentiodynamic polarization, chronoamperometric current-time, open-circuit potential, and electrochemical impedance spectroscopy measurements. The surface of the composites after their corrosion in the test solution was investigated using scanning electron microscopy and energy dispersive X-ray analyses. It has been found that all manufactured composites suffer uniform corrosion. All corrosion test techniques were consistent with each other and confirmed clearly that the corrosion resistance of Al composites increased according to their sintering temperature in the following order 900 > 1100 > 1300 °C.