Effects of metastable θ′ precipitates on the strengthening, wear and electrical behaviors of Al 2519-SiC/fly ash hybrid nanocomposites synthesized by powder metallurgy technique

In this work, the powder metallurgy technique was used to prepare hybrid Al-Cu-Si matrix nanocomposites with different proportions of SiC and fly ash to improve the mechanical and elastic properties and wear resistance Al-Cu-Mg matrix. Also, the effect of aging time on the wear behavior, mechanical and electrical properties of the fabricated nanocomposites were investigated. The results showed that increasing the weight percentages of the hybrid ceramics resulted in a weakening of the precipitation phase (theta') and a decrease in the crystal and particle sizes. Moreover, the mechanical properties of the prepared nanocomposites such as microhardness, Young's modulus and compressive strength showed significant improvement as they increased by 60, 32 and 43%, respectively. In comparison, the wear rate decreased by 51% after adding 8 wt.% SiC and 8 wt.% fly ash compared to matrix Al alloy. Similarly, the microhardness and compressive strength values increased by 38.1 and 48%, respectively. In comparison, the wear rate value decreased by 58% for the nanocomposite samples with the highest reinforcement content (ASF8) after 4 h of aging. Despite a slight decrease in the first hours of the aging process, the electrical conductivity of the sintered samples generally increased with the increase in the aging time. The ASF0 and ASF8 samples' maximum electrical conductivity values were 4.52 x 10(7) and 2.29 x 10(7) S/m, respectively, after 22 h of aging.

Automated summary

Hybrid Al-Cu-Si matrix nanocomposites with different proportions of SiC and fly ash were prepared using powder metallurgy technique to enhance the mechanical and elastic properties as well as wear resistance of Al-Cu-Mg matrix. The study also investigated the effect of aging time on the wear behavior, mechanical and electrical properties. The results showed that increasing the weight percentages of hybrid ceramics resulted in a weakening of the precipitation phase and a decrease in crystal and particle sizes. The prepared nanocomposites exhibited significant improvement in microhardness, Young's modulus, compressive strength, and reduced wear rate.