A study was made of the particles which strengthened a composite with an Al-alloy matrix. This indicated that particle cracking during mechanical testing markedly affected the failure of the composite. Micro-cracks nucleated and propagated on stacking faults and interfaces between 4H (or 3C) and 6H hexagonal phases within the carbide particles. These planar defects were the main ones in the particles. Partial dislocations, with a 1/3<10•0> Burgers vector, were also observed to bound the stacking faults.

S.G.Song, R.U.Vaidya, A.K.Zurek, G.T.Gray: Metallurgical and Materials Transactions A, 1996, 27[2], 459-65