Application‐Grade TiAl Single Crystal With Excellent Room‐Temperature Plasticity and Strength Prepared by Seeded Electromagnetic Confinement Directional Solidification

ABSTRACT In this study, a newly developed seeded electromagnetic confinement directional solidification (EMCDS) technique was employed to fabricate large‐scale TiAl single crystal ingots with a diameter of 32 mm, overcoming the long‐standing size limitations that have hindered their industrial application. With emphasis on the exceptional room‐temperature (RT) tensile properties ( ε = 4.6%, σ = 807 MPa) of these single crystals, the underlying deformation mechanisms were systematically investigated using multi‐scale characterization methods. The results show that ultra‐high density, interconnected slip bands are maintained on the fracture‐side surfaces of TiAl single crystal, providing direct evidence of substantial plastic deformation. Detailed analysis further indicates that the extensive activation of deformation twins within the γ lamellae is the main contribution to the high RT elongation. Notably, the presence of the 9R structure promotes strain delocalization between γ lamellae. During later stages of plastic deformation, numerous dislocations, stacking faults, and even phase transformations emerge within the α 2 lamellae, which subsequently coordinate the deformation of the γ phase. Moreover, twin intersections, dislocation entanglements, and interfacial dislocation networks induced by micro‐segregation of C and Si collectively serve as critical mechanisms for synergistic strengthening. This work clarifies the RT deformation mechanisms of multi‐component TiAl single crystals and opens new avenues for the design and development of advanced TiAl single crystals tailored for aerospace applications.