Microstructure and mechanical properties of large size Ti-43Al-9V-0.2Y alloy pancake produced by pack-forging

A pancake of Ti-43Al-9V-0.2Y (at.%) alloy with dimensions of 0480 mm x 46 mm was fabricated by pack-forging with a thick reduction of 80%. The as-forged Ti-43Al-9V-0.2Y alloy pancake has a duplex (DP) microstructure, which is composed of B2/alpha(2)/gamma lamellar colonies and massive B2 and gamma phase regions distributed along the boundaries between the lamellar colonies. Different microstructures were obtained by heat treatment of samples cut from the as-forged Ti-43Al-9V-0.2Y alloy pancake. A fully lamellar (FL) structure consisting of B2/alpha(2)/gamma lamellar colonies was obtained after the heat treatment of 1350 degrees C/8 h. Tensile test results exhibited that the yield strength (YS) and ultimate tensile strength (UTS) of the alloy with DP microstructure were decreased from 680.7 MPa to 834.3 MPa at room temperature to 589.5 MPa and 693.1 MPa at 700 degrees C, respectively, and the elongation (delta) of the alloy with DP microstructure was increased from 1.99% at room temperature to 12.12% at 700 degrees C; the elongation (delta) of the alloy with FL microstructure was increased from 1.52% at room temperature to 85.84% at 800 degrees C. (C) 2012 Elsevier Ltd. All rights reserved.