The effect of annealing treatment on the evolution of the microstructure, the mechanical properties and the texture of nano SiC reinforced aluminium matrix alloys with ultrafine grained structure

Abstract

In the present work, an ultrafine grained (UFG) aluminium matrix nano composite (UFANC) was prepared through a cryogenic deformation based manufacturing route. The influence of annealing on the microstructural evolution, mechanical properties and the crystallographic texture of the developed UFANC material was studied and compared with the unreinforced ultrafine grained counterpart (UFG). The presence of nano particles during deformation led to an increased generation of dislocations in the matrix. At low annealing temperatures high density dislocations provided a higher driving force for recrystallization in the UFANC. At high temperatures the grain growth in the UFANC was restricted by the pinning action of the nano reinforcement. This resulted in a higher activation energy for grain growth compared to the UFG counterpart. As a result, the UFANC retained high strength and possessed a fine microstructure even at annealing temperatures of up to 250 °C. The evolution of the texture during annealing was influenced due to the deformation at cryogenic environment. The presence of nano particles led to a more random texture in the UFANC compared to the UFG counterpart during annealing.