Tensile Property and Fracture Mechanism of Directionally Solidified Fe(Al, Ta)/Fe₂Ta(Al) Eutectic Composites

Fe-Al intermetallic compounds have received much attention as one of the high-temperature structural materials. In the present study, Fe(Al, Ta)/Fe₂Ta(Al) eutectic composites were prepared using the electron beam floating zone melting (EBFZM) directional solidification technique. Room and high-temperature tensile properties of the Fe(Al, Ta)/Fe₂Ta(Al) eutectic composites at different solidification rates were studied. Microstructure evolution and fracture mechanism during the fracture process were analyzed using in situ tensile tests. The results show that lamellar (rodlike) Fe₂Ta(Al) Laves phase becomes finer and more uniform with the increase in the solidification rate. The tensile strength of the Fe(Al, Ta)/Fe₂Ta(Al) eutectic composite increases with the increase in the solidification rate at the same tensile temperature. The tensile strength of the Fe(Al, Ta)/Fe₂Ta(Al) eutectic composite at 600 °C is weaker than that at room temperature at the same solidification rate. The fracture mechanism of the Fe(Al, Ta)/Fe₂Ta(Al) eutectic composite can be summarized as crack extension along the shear zone, crack passing through the Laves phase, crack extension along the phase interface and simultaneous extension of multiple cracks.