Wide-temperature range superelasticity in NiTiFe alloy by inducing strain glass transition via laser additive manufacturing

• NiTiFe R-STG alloy is fabricated by in-situ LPBF technique without post-processing. • Highly lattice distortion is achieved by introducing diverse micro-defects. • The alloy exhibit quasi-linear superelasticity over wide temperature span. • Demonstrated the feasibility of additive manufacturing for novel STG alloys. This study proposes a laser powder bed fusion strategy to achieve wide-temperature range superelasticity in NiTiFe alloys by inducing strain glass transition. Through innovative synergistic modulation of diverse micro-defects (Fe atom doping, dislocations, nanoprecipitates), long-range ordered martensitic transformation is suppressed, while enabling R-liked strain glass state formation without post-processing. The as-fabricated alloys exhibit quasi-linear superelasticity with low stress hysteresis and full recoverable strain over a temperature span from 300 K to 120 K, and temperature-insensitive low elastic modulus. This work offers a scalable framework for designing novel strain glass alloys via additive manufacturing, unlocking potential for wide-temperature functional applications.