Effect of pre-deformation in the β phase field on the microstructure and texture of the α phase in a boron-added β-solidifying TiAl alloy

Abstract

In this work, the effect of pre-deformation in the β phase field on the microstructural characteristics of α phase in a Ti-40Al-8Nb-0.5B alloy (at. %) was investigated. The results showed that the morphology and crystallography of α phase were strongly influenced by the deformation. It was observed that if there was no deformation, α laths which formed strict Burgers orientation relationship with β matrix are predominant (∼81% in number fraction). In contrast, the Burgers α laths are significantly reduced after compression in the β phase field. Meanwhile, an abnormal double-fiber texture, <11–20> and <10–10>, is produced. After systematic analysis, we believe that the reduction of Burgers α is attributed to the heterogeneous nucleation of α phase at borides and the breakdown of the boride ribbons during deformation. Moreover, the formation of α texture is a synergetic consequence of β texture and boride texture.