Isothermal forging of metal matrix composites: Recrystallization behaviour by means of deformation efficiency

Abstract The hot forming behaviour of 2618 aluminium alloy reinforced with 20% of Al 2 O 3 particles have been studied by employing both “processing maps” and microstructural observations. The material under investigations was deformed by torsion in the temperature and strain rate ranges 350–500 °C and 10 −3 –10 s −1 , respectively. The deformation efficiency was calculated by strain rate sensitivity ( m ) values obtained by hot torsion tests. The material showed a regime of dynamic recrystallization in the ranges 450–500 °C and 10 −2 –10 −1 s −1 corresponding to the higher values of efficiency. The material was characterized by employing optical and electron microscopy (SEM, TEM) to evaluate the microstructural transformations and instability phenomena.