Reaction pathway and phase transitions in Al–Ti–Si system during differential thermal analysis

• Published in: Solid state sciences 2010-08, Vol.12 (8), p.1347-1351
• Main Authors: Wang, Hui–Yuan, Zha, Min, Lü, Si–Jie, Wang, Cheng, Jiang, Qi–Chuan
• Format: Article
• Language: English
• Subjects: Aluminides; Aluminum; Condensed matter: structure, mechanical and thermal properties; Constant-composition solid-solid phase transformations: polymorphic, massive, and order-disorder; Cross-disciplinary physics: materials science; rheology; Differential thermal analysis; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; Expenses; Intermetallics; Materials science; Pathways; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Phase transformation; Physics; Silicides; Silicon; Solubility; Solubility, segregation, and mixing; phase separation; Specific phase transitions; Structural transitions in nanoscale materials; Titanium silicides; Transportation; X–ray diffraction
• ISSN: 1293-2558; 1873-3085
• DOI: 10.1016/j.solidstatesciences.2010.05.006

The present paper mainly studied the phase formation and reaction pathway of the Al–Ti–Si system in detail by thermal analysis combined with XRD and SEM observations. The phase formation sequence in Al–Ti–Si system from starting mixtures to final products with increasing temperature can be described as following: Al (l) + Ti (s) + Si (s) → (Al–Si) (l) + Ti (s) + Si (s) → Ti(Al,Si) 3(s) + Si (s)Ti 5(Si,Al) 3 + Al (l). More importantly, the solubility of Si in Ti(Al,Si) 3 decreased gradually while that of Al in Ti 5(Si,Al) 3 increased with temperature increasing, suggesting the transportation of Si atoms from intermediate aluminides Ti(Al,Si) 3 to final stable silicides Ti 5(Si,Al) 3 and hence further confirming the formation of Ti 5(Si,Al) 3 at the expense of Ti(Al,Si) 3. [Display omitted]