Microstructure of directionally solidified Ti–Fe eutectic alloy with low interstitial and high mechanical strength

The performance of Ti alloys can be considerably enhanced by combining Ti and other elements, causing an eutectic transformation and thereby producing composites in situ from the liquid phase. This paper reports on the processing and characterization of a directionally solidified Ti–Fe eutectic alloy. Directional solidification at different growth rates was carried out in a setup that employs a water-cooled copper crucible combined with a voltaic electric arc moving through the sample. The results obtained show that a regular fiber-like eutectic structure was produced and the interphase spacing was found to be a function of the growth rate. Mechanical properties were measured using compression, microindentation and nanoindentation tests to determine the Vickers hardness, compressive strength and elastic modulus. Directionally solidified eutectic samples presented high values of compressive strength in the range of 1844–3000 MPa and ductility between 21.6 and 25.2%.

► Moving electric arc setup was applied to directionally solidify Ti–Fe eutectic.
► Avoids oxygen contamination and produces aligned eutectic microstructure.
► Orientation relationship between β-Ti and TiFe phases is (1 1 3)β‖(1 1 3)TiFe.
► Microhardness values increased as the solidification rate increased.
► Samples presented compressive strength up to 3000 MPa and ductility up to 25.2 ± 2%.