Microstructural and nuclear magnetic resonance studies of solid-state amorphization in Al-Ti-Si composites prepared by mechanical alloying
Three Al{sub 30}Ti{sub 70-x} Si{sub x} (x=10, 20, 30), along with an Al-rich (Al{sub 50}Ti{sub 40}Si{sub 10}) and an Al-lean (Al{sub 10}Ti{sub 60}Si{sub 30}) elemental powder blends were subjected to mechanical alloying by high-energy planetary ball milling to yield a composite microstructure with varying proportions of amorphous and nanocrystalline intermetallic phases. Microstructural characterization at different stages of milling was carried out by X-ray diffraction, high-resolution transmission electron microscopy and energy dispersive X-ray spectroscopy. Furthermore, {sup 27}Al nuclear magnetic resonance (NMR) studies were undertaken to probe the mechanism of solid-state amorphization. Ball milling leads to alloying, nanocrystallization and partial solid-state amorphization followed/accompanied by strain-induced nucleation of nanocrystalline intermetallic phases from an amorphous solid solution. Both these amorphous and nano-intermetallic phases are associated with characteristic NMR peaks at lower frequencies (than that of pure Al). Thus, mechanical alloying of Al-Ti-Si appears a suitable technique for developing nanocrystalline intermetallic phase/compound dispersed amorphous matrix composites.
- OSTI ID:
- 20634744
- Journal Information:
- Acta Materialia, Journal Name: Acta Materialia Journal Issue: 14 Vol. 52; ISSN 1359-6454; ISSN ACMAFD
- Country of Publication:
- United States
- Language:
- English
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