Answer: Composites are classified into particle-reinforced (large-particle, dispersion-strengthened), fibre-reinforced (continuous aligned, discontinuous aligned or random) and structural (laminar, sandwich panels).
Tree chart (described): the top box "Composites" branches into three boxes; each of these branches into two further boxes, as below.
- Particle-reinforced composites
- Large-particle: particles larger than about 1 μm restrain matrix movement. Example: concrete (gravel and sand in cement), cemented carbide (WC in Co), carbon black in rubber tyres.
- Dispersion-strengthened: very fine particles (10–100 nm) block dislocation movement. Example: thoria-dispersed nickel (TD-Ni), sintered aluminium powder (SAP, Al₂O₃ in Al).
- Fibre-reinforced composites
- Continuous (aligned): long parallel fibres. Example: unidirectional carbon fibre–epoxy.
- Discontinuous (short): aligned or randomly oriented. Example: chopped glass fibre mat in polyester (GFRP sheets).
- Structural composites
- Laminar: example plywood, laminated glass.
- Sandwich panels: example aluminium face sheets on a honeycomb core in aircraft floors.
They can also be classified by matrix: polymer-matrix (PMC), metal-matrix (MMC) and ceramic-matrix (CMC) composites.
