Microstructure and mechanical properties of as-cast Ti–43Al–9V–0.3Y alloy

Microstructure and mechanical properties of an as-cast Ti–43Al–9V–0.3Y alloy have been studied. The alloy has the fine near lamellar microstructure with a lamellar colony size of about 80 μm, and a small amount of β + γ phases along colony boundaries. There also exist some β precipitations within the lamellar colonies, besides the α2 and γ lamellae. Some disperse Y-rich particles are found as the YAl2 phase. The alloy has moderate mechanical properties at room temperature and 700 °C. At room temperature, the ultimate tensile strength is about 511 MPa and the elongation is 0.5%. At 700 °C, the ultimate tensile strength decreases to about 426 MPa and the elongation increases to 5.7%. Cracks primarily propagate in transgranular mode in spite of the effect of test temperature.