Effect of Reinforcement Ratio and Aging Time on the Microstructure, Hardness, and Wear Behavior of ZrO2-Reinforced AA7075 Matrix Nanocomposites Produced by Powder Metallurgy
Journal of Materials Engineering and Performance, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Basım Tarihi: 2026
- Doi Numarası: 10.1007/s11665-026-14951-3
- Dergi Adı: Journal of Materials Engineering and Performance
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Applied Science & Technology Source, Chemical Abstracts Core, Compendex, INSPEC, Engineering Source (EBSCO), Materials Science & Engineering Collection (ProQuest), Technology Collection (ProQuest)
- Anahtar Kelimeler: AA7075, Aging treatment, Powder metallurgy, Precipitation hardening, Wear behavior, ZrO2 reinforcement
- Gazi Üniversitesi Adresli: Evet
Özet
This study investigates the combined effects of ZrO2 reinforcement ratio and aging heat treatment on the microstructural, mechanical, and tribological properties of AA7075 matrix composites produced via powder metallurgy. Composite specimens containing 1, 2, and 3 wt.% ZrO2 were aged at 120 °C for 3, 6, and 9 h to evaluate the influence of reinforcement content and aging duration. Microstructural characterization (OM, SEM, and XRD), relative density measurements, hardness testing, and dry sliding wear experiments were systematically conducted. The results show that ZrO2 addition modifies the microstructural morphology and promotes a relatively more uniform microstructural appearance, while localized particle clustering becomes evident at higher reinforcement contents. Aging treatment enhances precipitation processes within the Al matrix, resulting in a continuous increase in hardness and wear resistance. XRD analyses indicate that the Al matrix and stable ZrO2 phases dominate the diffraction patterns, while only subtle diffraction features tentatively associated with nanoscale MgZn2 and Al2CuMg precipitates are observed, reflecting their low volume fraction and coherent or semi-coherent nature. SEM analyses of worn surfaces reveal a clear transition in the dominant wear mechanism from adhesive to predominantly abrasive wear as the reinforcement ratio and aging time increase. This transition is attributed to the combined effect of ZrO2 particles acting as load-bearing elements and precipitation strengthening, which together enhance surface stability and limit localized plastic deformation during sliding. Among all conditions, the composite containing 3 wt.% ZrO2 aged for 9 h (9S3) exhibits the highest hardness and the lowest wear loss, indicating the most favorable overall mechanical and tribological performance. Overall, the results demonstrate that the synergistic interaction between reinforcement and aging provides an effective strategy for tailoring the microstructure-property relationship of AA7075-based powder metallurgy composites.