The influence of β-stabilizing elements on the solidification behavior and mechanical properties of the Zr-containing TiAl alloy

This study systematically investigates the influence of β-stabilizing elements (Cr, Mn, and Fe) on the solidification behavior and mechanical properties of the Ti-46Al-2Zr alloy. The introduction of β-stabilizing elements promotes the formation of the B2 phase and increases the content of the blocky γ phase. Additionally, the addition of Fe is associated with the emergence of the honeycomb τ₃ phase. The incorporation of Cr and Mn effectively refines both the grain size and interlamellar spacing, while the introduction of Fe slightly reduces interlamellar spacing but results in coarser grains compared to the matrix. Furthermore, the inclusion of β-stabilizing elements significantly enhances the room-temperature mechanical properties of the Zr-containing TiAl alloy, with Cr addition demonstrating the highest compressive strength and Mn addition resulting in the greatest fracture strain. The substantial improvement in compressive strength due to Cr addition is attributed to grain refinement strengthening, lamellar refinement strengthening, and solid solution strengthening. In contrast, the toughening mechanism induced by Mn addition involves the refinement of grains and lamellae, a reduction in the c / a ratio, and the formation of high-density nanotwins.