Microstructure, texture, and mechanical properties analysis of novel AA7178/SiC nanocomposites

Abstract

The current research aims to use stir casting to create a composite made from AA7178 aluminium alloy with nano SiC reinforcement at 1, 2, and 3 wt percent. Scanning electron microscope (SEM) with energy dispersive X-Ray (EDAX) was used to examine the microstructural changes of AA7178/nSiC composites. The addition of nano SiC reinforcement to the AA7178 matrix promotes grain refinement by providing additional nucleation sites for smaller grains to form. The microstructure of AA7178 composites underwent a considerable alteration due to the SiC addition, improving their mechanical properties. Electron backscatter diffraction (EBSD) study revealed the development of finer grains from coarser grains. All the samples seemed to have a completely random texture. The texture does not seem to be drastically altered by either the processing conditions or the incorporation of SiC. The uniform distribution of SiC particles and good interfacial bonding between the reinforcement matrix was confirmed by a transmission electron microscope (TEM). The maximum tensile strength was 206.12 MPa for AA7178 nanocomposite with 3 wt% of SiC reinforcement. The efficient transmission of load and dislocation strengthening were the strengthening mechanism for increasing in the tensile strength. The inclusion of 3 wt% of SiC particles increased the hardness of AA7178 nanocomposite to 51.70%.