The Effects of γ Phase on Superelasticity in Cu–Al–Mn Alloys Fabricated via Laser Powder Bed Fusion

The reversibility of shape memory alloys (SMAs) is crucial for superelastic applications. Although nanocrystalline structures improve superelasticity, achieving them in Cu–Al–Mn SMAs is difficult due to grain coarsening. Recent studies suggest nanoscale precipitates may enhance superelasticity without grain refinement. Here, nanoscale precipitates into laser powder bed fusion (L‐PBFed) Cu–Al–Mn alloys are introduced via aging to investigate their effects on phase transformation and superelasticity. Combining Computer Coupling of Phase Diagrams and Thermochemistry (CALPHAD)‐based phase diagram calculations with in situ X‐ray diffraction (XRD), two precipitates (α′ and γ) are identified as potential strengthening precipitates. With the help of nanoindentation test, γ precipitate is selected as the optimal strengthening phase due to its high hardness. Electron backscattered diffraction (EBSD) reveals a {0001} γ //{110} Aus orientation relationship and interfacial dislocation segregation between γ and austenite. Resistivity tests show lost thermal martensitic transformation in (austenite + γ) structure, but stress‐field cooling confirms stress‐induced martensitic transformation (SIMT) via negative thermal expansion. After aging at 250 °C for 180 min, tensile test shows linear superelasticity with enhanced modulus (66.7 GPa), reduced hysteresis‐to‐input energy ratio (4.4%) and full recovery (≈100%). These findings suggest that γ precipitate can enhance the superelasticity of Cu–Al–Mn SMAs, providing a new enhancing strategy.