Thermomechanical processing of Al based particulate composites.

Thermomechanical processing of aluminium-based particulate composites containing dispersions of various soft and hard particles such as graphite, zircon, glass, alumina and mica in aluminium alloy matrices, with a view to improving strength and ductility for structural applications, has been discussed. The existing literature on the subject has been critically reviewed and analysed, and broad guidelines for optimum thermomechanical processing have been presented. Considerable improvements in strength and ductility of these composite materials have been reported after rolling, forging and extrusion due to fragmentation/fibrization of particles together with the refinement of matrix microstructure, annihilation of defects such as porosity, and texture hardening, etc. The influence of process variables, and of volume fraction, size and morphology of the particles on the strengthening mechanisms, fracture toughness and work-hardening behaviour of worked composites has been discussed