Mechanical Properties and Plastic Deformation Mechanism of Additively Manufactured Novel Metastable b Ti–42Nb and Near b Ti–20Nb–6Ta Alloy

b-Titanium alloys are gaining attention for biomedical applications due to their superior corrosion resistance, excellent biocompatibility, and low Young’s moduli. This study investigates the mechanical properties of novel metastable b Ti–42Nb and near b Ti–20Nb–6Ta alloys processed through laser powder bed fusion. Utilizing the d-electron alloy design method, predictions were made regarding Young’s modulus and plastic deformation behavior prior to experimental testing. The correlation between the mechanical properties and microstructural characteristics was examined using X-ray diffraction, scanning electron microscopy, and electron backscatter diffraction. Results indicated that both Ti–42Nb and Ti–20Nb–6Ta exhibited improved ductility and lower Young’s modulus compared to pure titanium and Ti–6Al–4V processed by the same method. Interestingly, the orthorhombic a¢¢ phase of Ti–20Nb–6Ta showed an even lower Young’s modulus than the b phase of Ti–42Nb, while displaying higher strength simultaneously. Further microstructure analyses revealed no stress-induced phase transformations or twin formations for the alloys examined, aligning well with the predictions made by the d-electron alloy design method.