In situ Carbide Strengthening for Enhanced 800 °C Tensile Performance of As‐Cast High‐Nb TiAl alloy

In this study, the Ti45Al8Nb‐0.6C alloy is synthesized via vacuum induction melting, exhibiting a homogeneous microstructure composed of (γ‐TiAl + α 2 ‐Ti 3 Al) lamellae, B2 phase, and γ phase across its top, middle, and bottom sections. High‐temperature tensile tests demonstrate an ultimate tensile strength of 501 MPa, highlighting its potential for elevated‐temperature applications. The fracture surface exhibits a predominantly brittle mode, with grain boundary separation, interlamellar cleavage, crack deflection, and pull‐out of reinforcing phases. Notably, the pull‐out of Ti 2 AlC particles indicates that this phase contributes to energy dissipation and thus affected high‐temperature fracture behavior. The B2 phase is uniformly distributed within the lamellar matrix, with pronounced dislocation accumulation observed at B2/γ interfaces during high‐temperature deformation. Concurrently, in situ formed Ti 2 AlC precipitates effectively hinder deformation twin propagation and dislocation motion. This synergistic interaction between the B2 phase and Ti 2 AlC particles leads to a substantial improvement in the alloy's overall mechanical performance. These findings offer critical insights into the rational design of high‐performance TiAl‐based alloys, enabling their application in advanced aerospace and automotive engineering.