Investigation of the Effect of Sr on the Mechanical Properties and Microstructure of Nano-Alumina Reinforced Aluminum Matrix Composites by the Vortical Casting Method

In this study, the vortical casting used to prevent the agglomeration of alumina nanoparticles in molten aluminum, and the various aspects were studied. The influence of strontium as a reformer material on the microstructure of the A356 aluminum composite substrate, nano-alumina, and micro-copper reinforcing particles investigated. The alumina nanoparticles and the microparticles of copper milled and the mixed powder added to produce the composite A356. 1.5 vol% nano Al2O3/Cu vortex of the molten aluminum in the casting process, and different amounts of sr were added to the melt separately. The results of this study showed that the optimum amount of Sr to modify the eutectic structure of silicon and improve the wettability of the A356 alloy is 0.5% strontium, which shows the results of the X-ray map analysis of the Sr separation on the particle-matrix interface. The consumed a fraction of the strontium in the matrix. The strontium separation in the particle-matrix interface can lead to the improved wettability of the alumina nanoparticles. Higher amounts of 0.5% volumetric strontium lead to the formation of intermetallic Al2Si2Sr particles. Also, the highest strength at 0.5% volumetric strontium, 191 MPa reported.

Automated summary

The study investigated the use of vortical casting to prevent the agglomeration of alumina nanoparticles in molten aluminum, with a focus on the influence of strontium as a reformer material on the microstructure of the composite substrate. Results showed that the optimal amount of strontium for modifying the eutectic structure of silicon and improving the wettability of the A356 alloy is 0.5%. Higher amounts of strontium led to the formation of intermetallic Al2Si2Sr particles, with the highest reported strength at 191 MPa.