Particle–matrix interface microstructure of in situ TiCp–AlNp/Al composite

Metal–matrix composites reinforced with sub-micrometre particles of TiC and AlN are made by in situ reaction of CH4 and NH3 gases with an Al–6.2Ti–4.6Mg (wt.%) melt, with a range of processing conditions being explored. High-resolution electron microscopy of the particle/matrix interfaces show that in all cases they are clean and well bonded. The orientation relationships between the various types of particle and the matrix are examined. In samples where the Ti is completely consumed by the reaction, the TiC particles are coated with a thin layer of Al3Ti. The presence of this layer has little effect on the mechanical properties of the composites.