As a representative γ-TiAl alloy, the TNM alloy has a low density and high specific strength, demonstrating significant potential for application in the aerospace industry. However, its pronounced room-temperature brittleness and complex deformation mechanisms pose challenges for conventional tensile testing, which is limited in capturing the evolution of localized strain. This constraint hinders the optimization of its forming processes and broader application. Therefore, there is a pressing need for an effective and precise method to characterize its deformation behavior. Digital image correlation (DIC), an emerging technique, offers advantages such as a broad measurement range, high accuracy, and noncontact operation. This enables visualization of the strain distribution and displacement evolution during deformation.

Nevertheless, its application in studying strain and displacement variations in TNM alloys during room-temperature tensile testing remains limited. To address this gap and provide a clear depiction of the strain and displacement distribution behavior of the TNM alloy under room-temperature tension, this study employed DIC equipment and its associated software, Istra 4D. The results indicate that the true stress-strain curve of the TNM alloy during room-temperature tensile testing consists of elastic deformation and work hardening stages, without a distinct yield plateau. The ultimate tensile strength is measured as 464.35 MPa, with a postfracture elongation of 3.39% . Using DIC, the strain distribution and displacement changes during the tensile process are successfully captured. The quality of the speckle pattern used in the experiment is found to be satisfactory. The displacement exhibits an approximately linear increase over time, characterized by significant fluctuations in the early stages and a more stable trend in the later stages. This study confirms the applicability of the DIC method in analysing the tensile deformation behavior of TNM alloys. The DIC technique enables full-field, noncontact deformation measurements across macroscopic to microscopic scales, revealing deformation

inhomogeneities, localization phenomena, and their correlation with microstructural features that are not detectable via conventional methods. Furthermore, it facilitates in situ, multiscale, and multiphysical field coupled analysis, thereby providing essential experimental data for understanding complex deformation mechanisms and damage progression and for validating advanced material models.