Fig 1. SEM micrographs of (a) Ti64 powders, (b) 5% YSZ+Ti64 powders, (c) YSZ nanoparticles coated on the surface of the 5% YSZ+Ti64 powder, (d) schematic illustration of laser head and deposited sample geometry.

Fig 2. (a) Temperature change and the corresponding heating and cooling rates during the initial stages of a single cycle of Ti64. The cooling rate is averaged over a period of 16 ms. The release of the latent heat caused by the solidification is marked by an arrow. (b) The thermal cycles at different locations of 1 and 12 mm away from the initially deposited surface. The temperature increase due to the diffusional transformation from β to α and the associated release of latent heat is marked by an arrow.

Fig 3. XRD patterns of the 5% YSZ+Ti64 powder, and the as-deposited Ti64, 0.5%, 1%, and 5% YSZ+Ti64 sample. Left: Detail scan of the α peak. Samples for XRD analyses were taken from the center regions of the as-deposited samples.

Fig 4. OM micrographs of as-deposited (a) Ti64, (b) 0.5% YSZ+Ti64, (c) 1% YSZ+TI64, and (d) 5% YSZ+Ti64. OM analyses were performed for the center regions of the as-deposited samples.

Fig 5. EBSD IPF and phase maps of as-deposited (a) Ti64, (b) 0.5% YSZ+Ti64, (c) 1% YSZ+Ti64, and (d) 5% YSZ+Ti64 parallel to the building direction. EBSD analyses were performed for the center regions of the as-deposited samples.

Fig 6. (a, b) HAADF-STEM images. The FFT pattern in the dash square in (b) reveals the existence of β between lath-shaped α grains. (c, d) correspond EDS maps of V and Al.

Fig 7. (a) HAADF-STEM micrographs of as-deposited 5% YSZ+Ti64 and (b) EDS maps corresponding to Y, showing Y2O3 nanoparticles distributed in the α phase. (c) HRTEM micrographs of interface between the α phase and Y2O3 particle and corresponding FFT pattern.

Fig 8. (a) Reconstructed 3D atom map of as-deposited 5% YSZ+Ti64. (b) solute frequency distribution analysis of a subvolume of Ti, Al, V, Zr, and O respectively. (c) Magnified view of Y2O3 nanoparticles highlighted by 3 at.% Y (red) and 4.5% O (cyan) isoconcentration surfaces. (d) 1D concentration profiles measured horizontally along the Y2O3 nanoparticles in as-deposited 5%ZTi. Orange, blue, violet, red, cyan, purple, and green lines represent atomic concentrations for Ti, Al, V, Y, O, and Zr, respectively.

Fig 9. Engineering tensile stress-strain curves of as-deposited Ti64 and 0.5%, 1%, and 5% YSZ+Ti64.

Fig 10. (a) Calculated phase fractions of α, β, L, and Y2O3 as a function of temperature for 5% YSZ+Ti64 alloys with a multicomponent Ti-10.53Al-3.55V-0.83Zr-1.93O-0.09Y (at.%). The simulations were performed with the ThermoCalc software using TCTi1. (b) Normalized driving force (-ΔG∕RT) of oxides in the investigated alloy.

Fig 11. TTT diagram for grain boundary α (αGB) and Widmenstätten α (αw) in Ti-6Al-4 V (Ti64) and 5% YSZ+Ti64, calculated by JMatPro®.

Fig 12. (a) Yield strength plotted against the inverse square root of the α lath thickness for Ti-6Al-4 V (Ti64) and YSZ+Ti64 (literature and this study) and (b) summarized chart showing calculated strengthening contributions from refined alpha width and O solid solution.