Investigation Techniques of In Situ AlMg/AlN Metal Matrix Composites via Reactive Gas Injection

In this paper characteristics of an AlMg/AlN composite produced in-situ and processed in a flowing N2 atmosphere is investigated. Some critical parameters such as the manufacturing process temperature, the percentage of the magnesium consumed, the flowing reactive gas flow and the time for completing the manufacturing are considered as variables for the parametric investigation. Moreover, the effect of different amount of Mg employed has been also investigated, since Mg acts as a catalyst at the surface both for the gas/liquid and solid/liquid systems. Traditional methods were used for the basic characterization of the composite. The microstructure of the composite was investigated by optical and scanning electron microscopy (OM, SEM). SEM analysis was performed in order to observe the microstructural evolution as a function of the Mg content and to identify some reasons of the presence of porosity or any irregularities within the metal matrix. The evolution of mechanical properties, in terms of microhardness, at different percentage of Mg were monitored. By EDS technique the distribution of the elements was obtained. Furthermore, employing an optimization process, uniform dispersion of the strengthening (AlN) particles in the metal matrix with homogeneous properties along the composite material is obtained. Based on the aforementioned statements, it can be concluded that the reactions between Al, Mg and the N2 atmosphere induce spontaneous infiltration in the metal matrix. The complete mix of properties and experimentally assessed parameters can be used for industrial purpose manufacturing design and development.