<p>This study investigates the effects of aging treatments on the phase transformation behavior, microstructural evolution, and functional performance of Ni₅₄Ti₄₄Ta₂ shape-memory alloys. Differential scanning calorimetry (DSC), x-ray diffraction (XRD), scanning electron microscopy (SEM), and mechanical testing were employed to evaluate the behavior of homogenized and aged samples. The results reveal that 450 °C aging induces multiple phase transformations with broad thermal peaks, while aging at 600 °C suppresses transformation. Double aging at 600 °C for 3h followed by 450 °C for 3 h leads to a two-step transformation during cooling and a single-step austenitic transformation during heating. XRD analysis confirmed the presence of B2 austenite matrix with Ni₄Ti₃ and Ni₃Ti₂ precipitates in aged specimens. SEM revealed the evolution from a relatively homogeneous microstructure in the homogenized state to a dense distribution of plate- and needle-like precipitates after aging. SEM coupled with energy dispersive spectroscopy (EDS) analysis further indicated Ni enrichment in precipitates, accompanied by relative Ni depletion in the matrix, with Ta showing a tendency for segregation. Stress-assisted transformation behavior exhibited maximum recoverable strain of 1.45% under 400 MPa with increased transformation temperatures and hysteresis. Overall, thermal and mechanical responses demonstrate that aging treatments significantly enhance thermal stability and tailor the transformation characteristics of Ni₅₄Ti₄₄Ta₂ offering promising potential for shape-memory applications.</p>