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

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)Ti5(Si,Al)3 + Al(l). More importantly, the solubility of Si in Ti(Al,Si)3 decreased gradually while that of Al in Ti5(Si,Al)3 increased with temperature increasing, suggesting the transportation of Si atoms from intermediate aluminides Ti(Al,Si)3 to final stable silicides Ti5(Si,Al)3 and hence further confirming the formation of Ti5(Si,Al)3 at the expense of Ti(Al,Si)3.

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