Wire-based electron beam additive manufacturing of NiTiNb shape memory alloy: Microstructure, phase-transformation behavior and mechanical properties

NiTiNb shape memory alloy (SMA) is considered to have great potential in aerospace due to its wide phase-transformation hysteresis. Here, we innovatively used electron-beam additive manufacturing (EBAM) to fabricate a NiTiNb SMA thin-walled structure. The phase-transformation temperature, microstructure evolution, and mechanical properties were investigated in detail. The as-built NiTiNb SMA comprised a NiTi matrix and different morphologies of β-Nb phase at room temperature. The microstructure homogeneity and mechanical properties of NiTiNb prepared by EBAM significantly improved compared with those of NiTiNb powder-based AM technology. Our work provided a promising method for the preparation of defect-free and microstructure homogeneous NiTiNb SMA by AM. This method further stimulated the potential of additively manufactured SMA components for industrial applications.