Carbide Particle Reinforced Aluminum Matrix Research Articles

Micro-EDM for an Aluminium Matrix Composite

The silicon carbide particle reinforced aluminium matrix composite (SiCp/Al) which is acknowledged as one of the most competitive metal matrix composites is now widely applied in aviation, aerospace and military fields, and its application is extending gradually. As a result of the hard and brittle SiC particles contained, mechanical machining of the material is difficult, but the method of electric discharge machining (EDM) has certain prominent advantages. In this paper, SiCp/Al was machined using micro-EDM. First, a Ф40μm × 4.1mm micro tool electrode of which the aspect ratio is up to 100 was made; and then, through experiment, the impact of open-circuit voltage and electrode material on processing speed and electrode wear was analyzed; finally, 28μm wide micro slits, micro square platform of 34μm long on each side and other micro three-dimensional structure were machined. Research and experimental results show that the use of appropriate micro-machining parameters and reasonable processing methods can improve processing performance to better achieve the micro-EDM of SiCp /Al.

Effect of materials and modelling on the design of the space-based lightweight mirror

This paper focused on the application of finite element analysis in the design and validation of a space-based lightweight mirror. Reaction-bonded silicon carbide (RB SiC) and silicon carbide particle reinforced aluminum matrix composites (SiC p/Al) were selected as candidate materials for the mirror, and the finite element model created by discretizing the mirror assembly was employed to predict the performance of the mirror. The results indicated that RB SiC offered more excellent characteristics relative to other traditional materials and was a better candidate for space application in comparison with SiC p/Al.

Acoustic emission from particulate-reinforced metal matrix composites

A systematic study of the effect of microstructural parameters on the fracture behaviour of silicon carbide particle reinforced aluminium matrix composites has been carried out. Acoustic emissions have been monitored during tensile testing, giving the size and number of emmissions as a function of strain. This has been shown to be simply related to the rate of void nucleation at the reinforcing phase. Both particle fracture and particle/matrix decohesion mechanisms can be detected. Void nucleation was observed from the onset of plastic deformation and a linear relationship between damage initiation rate and strain was found. The rate of emission increased with reiforcing particle size and volume fraction but was independent of matrix alloy composition and heat treatment. These results show that the failure strain of particulate metal matrix composites is not controlled solely by the onset of void nucleation at the reinforcing phase. Local failure processes in the matrix are shown to promote void coalescence and dominate the ductility. However, suppression of void nucleation at the particles increases the ductility. It is suggested that a critical number of fractured particles is required before failure.