Characterisation of rosette formation in an aluminium–silicon alloy

Deni Ferdian (1, 2) , Yannick Thébault (1) , Alexandre Freulon (1) , Jacques Lacaze (1)

1 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux
2 UI - University of Indonesia

Differential thermal analysis has been used to investigate the effect of cooling rate on rosette formation during solidification of a synthetic Al–Fe–Si alloy. Rosettes can be characterised as a very fine multiphase structure within more or less convex areas dispersed in the matrix. Their formation during solidification is related with liquid entrapment and high solidification undercooling associated with the need of independent nucleation events of second phases. It is here shown that their density and internal coarseness depend on cooling rate. Further, metallographic observation of rosettes in contact with large precipitate of b-Al9Fe2Si2 phase allowed to conclude that this latter phase does not help silicon nucleation.

Mots clés: Al–Si alloys; Differential thermal analysis; Solidification sequence; Eutectic undercooling; Rosette

Domaines: Matériaux

Deni Ferdian, Yannick Thébault, Alexandre Freulon, Jacques Lacaze. Characterisation of rosette formation in an aluminium–silicon alloy. International Journal of Cast Metals Research, The, 2015, 28 (5), pp.290-294. ⟨10.1179/1743133615Y.0000000014⟩. ⟨hal-01481000⟩