Page 59 - MSAM-1-3

Materials Science in Additive Manufacturing Characterization of TPMS structures

A B C

E F
D

Figure 9. The EBSD orientation maps of the as-built and the heat treatment structures. (A) and (D) show the diagrams of the top and side scanning regions,
respectively. (B) As-built structure, region A1. (C) Structure after stress relief heat treatment, region A1. (E) As-built structure, region A2. (F) Structure
after stress relief heat treatment, region A2.
structural surface affected the measurement results. A B
Hence, in the remainder of this study, the theoretically
calculated relative density, instead of the measured
value, was used.
3.2. Microstructure analysis

In general, the solidification of Ti6Al4V during printing
process starts with the melted deposit, which consists of the
liquid β phase. As reported by Zhao et al. , due to the high
[24]
cooling rates, further cooling leads to the transformation C
from the β phase to martensite phase (α') phase during the D
LPBF process. Figure 9A and D show the scanning regions
of the EBSD maps, and Figure 9B and E and Figure 8C and
F show the microstructures of the as-built and heat-treated
Ti6Al4V samples, respectively. As shown in Figure 9B
and E, the EBSD orientation maps of the as-built Ti6Al4V
samples show that the original β grains and acicular α/α'
within each β grain. The white dotted lines in the figures
indicate the original β grain boundaries. Compared with
the results reported by Chang et al. and Vrancken et
[25]
al. , the length of the original β grains in this study is Figure 10. EBSD phase mapping of the LPBF-produced Schwarz-P
[26]
structures. (A) and (C) show the phase mapping of region A1 and A2 in
smaller (approximately 25 μm). Meanwhile, as reported by the as-built samples, respectively. (B) and (D) show the phase mapping of
Zhao et al. , the original β columnar grains are parallel to region A1 and A2 in the samples after stress relief heat treatment.
[24]
Volume 1 Issue 3 (2022) 8 http://doi.org/10.18063/msam.v1i3.17