Enhancing corrosion resistance through crystallographic texture control in additively manufactured superelastic NiTi alloy

NiTi alloys, widely used for their shape memory and superelastic properties, face corrosion challenges when fabricated via laser powder bed fusion (LPBF). This study investigates the dual-phase formation in LPBF NiTi and its impact on corrosion resistance. Thermal simulations and microstructural analysis reveal that thermal stress drives martensite formation near melt pool boundaries. Martensitic regions act as anodic sites, leading to localized corrosion. Optimizing LPBF parameters produced single-phase [001]-textured NiTi, eliminating martensite and significantly reducing the corrosion current by almost two orders of magnitude and enhancing superelastic performance simultaneously. These findings highlight texture control as a key strategy to improve corrosion resistance and functionality for advanced applications. • The formation mechanism of a dual phase microstructure in NiTi alloy is revealed. • Martensite acts as anode jeopardizing the corrosion resistance of the NiTi alloy. • Optimized process parameters to fabricate a single phase microstructure with [001]-texture are proposed. • Single-phase NiTi exhibits emhanced corrosion resistance and superelasticity.