Effects of Plastic Deformation and Aging Treatment on Phase Precipitation in Ti2AlNb Alloy

Ti2AlNb alloy has great potential for application as a structural material in aircraft manufacturing due to its excellent mechanical properties. In this study, the Portevin-Le Chatelier effects of Ti2AlNb alloy were at first studied by tensile tests, and the enrichments of Mo, Nb, Zr, and Ti atoms around dislocations were observed by transmission electron microscopy. Subsequently, the material was processed by compression and aging treatments and applied to investigate the effects of elemental clusters on the nucleation and growth of the O phase and α2 phase. Experimental results demonstrated that Al and Ti atoms are enriched around grain boundary and promote the α2 phase precipitation. Meanwhile, the clustering and segregation of Al and Ti atoms inhibit the growth of the O phase. The content of α2 and O phase precipitation is closely related to segregated atoms induced by plastic deformation and aging treatment. Under the thermo- mechanical processing conditions, the following Burger’s orientation relationships can be obtained: {001}O//{011}B and <110>O//<1-11>B, <11-20>α2//<111>B, and {0001}α2//{011}B. The tensile properties of the material processed by plastic deformation and aging treatment were mainly influenced by α2 phase precipitation around the grain boundary. This study deepens the understanding of phase precipitation and renders assistance to control phase precipitation of Ti2AlNb alloy.