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 mu m, and a small amount of beta + gamma phases along colony boundaries. There also exist some beta precipitations within the lamellar colonies, besides the alpha(2) and gamma lamellae. Some disperse Y-rich particles are found as the YAl2 phase. The alloy has moderate mechanical properties at room temperature and 700 degrees C. At room temperature, the ultimate tensile strength is about 511 MPa and the elongation is 0.5%. At 700 degrees 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. Crown Copyright (C) 2008 Published by Elsevier B.V. All rights reserved.