Synergistic Effect of In-Situ Al-7075/Al3Ti Metal Matrix Composites Prepared via Stir-Assisted Ultrasonic Melt Processing Under Dynamic Nucleation

S. V. Sujith, Hansoo Kim, Rahul S. Mulik, Hyeonwoo Park, Joonho Lee

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

Abstract: Owing to the high propensity for particle agglomeration, the fabrication of aluminum matrix composites with uniform distribution using casting routes is extremely difficult. In this study, the in-situ development of the Al3Ti reinforcing phase by employing stir-assisted ultrasonic treatment was utilized to improve the homogeneity, wettability, and thermodynamic stability of the reinforcing particles in an Al-7075 alloy matrix. The in-situ Al3Ti particles acted as heterogeneous nucleation sites and facilitated grain refinement to form a non-dendritic globular structure compared with the dendritic cells of the base alloy. The grain size of the α-Al dendrites reduced from 160 µm to 65, 50, and 40 µm with the addition of 2, 5, and 7 wt% Al3Ti, respectively. The reduction in the porosity of the composites and the improvement of the particle homogenization were due to cavitation-induced de-agglomeration and the degassing effect. The formation of a robust and clean interface between the Al3Ti particles and Al alloy via ultrasonic vibration improved the integrity of the composites compared with that of the base alloy. The thermal expansion mismatch between the Al3Ti particles and Al alloy contributed significantly to the improved mechanical properties of the composites. Graphic Abstract: [Figure not available: see fulltext.].

Original languageEnglish
JournalMetals and Materials International
DOIs
Publication statusAccepted/In press - 2021

Keywords

  • Fractography
  • Heterogeneous nucleation
  • In-situ casting
  • In-situ composite
  • Strengthening mechanisms
  • Ultrasonic cavitation

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys
  • Materials Chemistry

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