Effect of microstructure modulation on mechanical properties of Ti-Fe-Sn ultrafine eutectic composites

A series of (Ti70.5Fe29.5)100−xSnx alloys with x=0, 1, 3, 5, 7 and 9 were fabricated by a suction casting into cylindrical rods with a 3 mm diameter and 50 mm length. Microstructural investigations of these alloys revealed that Sn addition was effective in modulating the phase selection, length-scale of eutectic spacing and morphology of the colony in ultrafine eutectic structures upon solidification. The spherical morphology of the ultrafine eutectic colony was effective in enhancing the plastic strain in the samples. On theother hand, the formation of the bimodal eutectic structure stemming from a large temperature difference between two eutectic temperatures had a strong influence on modulating the phase selection and length-scale of the ultrafine eutectic structures and on controlling the strength and plastic strain of the ultrafine eutectic composites.