Laser powder bed fusion of superelastic Ti-18Zr-14Nb alloy: influence of processing and post-processing parameters on structure, texture, and functional properties

The effect of laser powder bed fusion parameters on the phase composition, structure, texture and density of Ti-18Zr-14Nb (at.%) alloy was studied. Based on the results obtained, the values of laser power, scanning speed, hatching space, and layer thickness leading to the fabrication of fully dense specimens were determined. These specimens were then subjected to different post-processing treatments: a) annealing at 500 and 700^oC (30 min) and b) combination of hot isostatic pressing (700^oC, 100 MPa, 90 min) and annealing (500^oC, 30 min) to measure the influence of these treatments on the material structure, texture, static and fatigue mechanical properties. The highest number of cycles (~2500) during high intensity strain-controlled fatigue testing (2% of strain in a cycle) was obtained after 500^oC annealing, whereas the lowest number of cycles was obtained after a combined HIP-annealing post-treatment (~200). A beneficial combination of static (YS=580 MPa, UTS=620 MPa, d=15%) and fatigue mechanical properties with a relatively low Young’s modulus (~48GPa) makes 500^oC-annealed laser powder bed-fused Ti-18Zr-14Nb components suitable for biomedical applications.