Layered AA7075/B4C/GNP Hybrid Composites: Processing, Characterization and Ballistic Resistance

Özer M., Yaman G., Taşcı U., Karakoç H., Özer A., Çinici H.

CERAMICS INTERNATIONAL, vol.2025, no.1, pp.1-15, 2025 (SCI-Expanded)

  • Publication Type: Article / Article
  • Volume: 2025 Issue: 1
  • Publication Date: 2025
  • Doi Number: 10.1016/j.ceramint.2025.09.191
  • Journal Name: CERAMICS INTERNATIONAL
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Chemical Abstracts Core, Communication Abstracts, Compendex, INSPEC, Metadex, Civil Engineering Abstracts
  • Page Numbers: pp.1-15
  • Gazi University Affiliated: Yes

Abstract

This study presents the fabrication and evaluation of bilayer aluminum matrix composites based on AA7075 alloy, reinforced with boron carbide (B4C), graphene nanoplatelets (GNPs), and potassium titanium fluoride (K2TiF6). A hybrid processing route—combining powder metallurgy, stir casting, and squeeze casting—was employed to produce layered structures with reinforcement-specific configurations. Mechanical characterization showed that increasing GNP content slightly reduced relative density (from 98.6% to 96.6%) while significantly enhancing microhardness (up to 194.1 HV0.5) and transverse rupture strength (up to 680 MPa). Ballistic performance, evaluated against 7.62×51 mm armor-piercing projectiles under NIJ Level III standards, revealed that the N3 composite with 1 wt.% GNP achieved the highest ballistic limit velocity (V50 ≈ 620 m/s), compared to 595 m/s for the monolithic AA7075 reference. These improvements are attributed to the combined influence of the ceramic and carbon-based reinforcements, along with the flux agent, which together enhanced interfacial bonding and mechanical response. The results indicate that the developed bilayer composites are promising candidates for advanced lightweight armor applications.

This study presents the fabrication and evaluation of bilayer aluminum matrix composites based on AA7075 alloy, reinforced with boron carbide (B4C), graphene nanoplatelets (GNPs), and potassium titanium fluoride (K2TiF6). A hybrid processing route—combining powder metallurgy, stir casting, and squeeze casting—was employed to produce layered structures with reinforcement-specific configurations. Mechanical characterization showed that increasing GNP content slightly reduced relative density (from 98.6% to 96.6%) while significantly enhancing microhardness (up to 194.1 HV0.5) and transverse rupture strength (up to 680 MPa). Ballistic performance, evaluated against 7.62×51 mm armor-piercing projectiles under NIJ Level III standards, revealed that the N3 composite with 1 wt.% GNP achieved the highest ballistic limit velocity (V50 ≈ 620 m/s), compared to 595 m/s for the monolithic AA7075 reference. These improvements are attributed to the combined influence of the ceramic and carbon-based reinforcements, along with the flux agent, which together enhanced interfacial bonding and mechanical response. The results indicate that the developed bilayer composites are promising candidates for advanced lightweight armor applications.