Improvement of room temperature ductility for Mo and Fe modified Ti2AlNb alloy

The effect of hot bar rolling and a subsequent annealing in the (B2 + α2) two-phase region on the mechanical properties was investigated for the Ti–25Al–14Nb–2Mo–1Fe (mol%) orthorhombic phase base alloy. After this thermomechanical treatment in the (B2 + α2) two-phase region, a ‘Van Goghʹs Sky (VGS)’ structure, with wavy and curled bands of spherical α2 precipitates, was obtained. Electron probe micro-analysis (EPMA) examinations indicated that the VGS bands correspond to the Nb and Mo lean regions. The width and spacing of VGS bands varied with thermomechanical treatment conditions (forging temperature before hot bar rolling as well as annealing temperature after the rolling). The samples with the VGS structure exhibited the higher tensile elongation-to-failure at room temperature. The creep resistance at 923 K decreased with the existence of the VGS structure. These mechanical properties were affected by the width and spacing of the VGS bands.