Fig. 1. Ti-6Al-4V deposited block prepared by LDM technology and sampling position. (a) Typical macromorphology of the sample at deposited state; (b) size of plate tensile sample; (c) sampling position of plate tensile sample and the observation plane of the microstructure (shaded surface);(d) 5 groups of plate tensile samples after machining

Fig. 2. XRD spectra of Ti-6Al-4V alloys with different B contents prepared by LDM process

Fig. 3. Morphologies of microstructures of Ti-6Al-4V alloys with different B contents prepared by LDM technology, arrows show TiB whiskers. (a) (b) 0.00% B; (c)(d) 0.05% B; (e)(f) 0.50%

Fig. 4. The variation trend diagrams of primary β columnar crystal diameter and ratio of length to width of lamellar α phase with B content

Fig. 5. Bright-field TEM image of TiB and selected area electron diffraction pattern (bottom left corner) in sample with B content of 0.10%

Fig. 6. Tensile curves of Ti-6Al-4V alloys with different B contents prepared by LDM technology

Fig. 7. Coordination effect of TiB on deformation during tension. (a) Large-size slip band in Ti-6Al-4V alloy without B; (b) obstruction and coordination of deformation by TiB when B content is 0.2%; (c) needle-like TiB fractures during deformation, forming continuous holes in the matrix; (d) lamellar TiB is broken during deformation, forming a plastic fracture surface on the interface of matrix

Table 1. Chemical compositions of Ti-6Al-4V titanium alloy powder