Ceramic reinforcement particles are coated with sufficient matrix material such that, on hot consolidation, the deposited material superplastically deforms and diffusion bonds to produce a fully-dense metal matrix composite without the addition of further matrix material. The ceramic powder may be coated using any known physical vapour deposition technique, on condition that a suitable arrangement is provided to ensure that the particles become evenly coated. During the coating process the powder is contained in a tray exposed to the deposition flux, even coating being achieved by motion of the tray (eg by tilting as illustrated in Fig 1) or by stirring of the particles. The tray may also be subjected to periodic shock or impulse loading. In another embodiment the tray may be rotated, a stationary comb being mounted above the tray with its teeth in contact with the charge. Upon rotation the charge is stirred by the teeth of the comb to expose fresh surfaces of the ceramic particles to the coating flux. More than one physical vapour deposition step may be employed. The ceramic particles may be formed of silicon carbide and the metal matrix material may be Ti-6Al- 4V alloy. IMAGE
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