Page 32 - MSAM-1-4

Materials Science in Additive Manufacturing Process optimization of SEBM IN718 via ML

structure has a MUD value of 1. In comparison, sample The bottom half of these regions reserved a hemispherical
P2 has the least area of grains in random orientations. shape. Compared with the microstructure of pre-alloyed
powder, it indicated that the fine grains may be inherited
A B from the incompletely melted powder . Columnar grains
[51]
were formed after <100> preferential growth on equiaxed
grains. The columnar grains are interrupted when coming
across the next unmelted powder. Variations of the
columnar grain width measured using the interception
method according to ASTM E112-2013 standard are listed
in Table 5. Samples P1, P2, and P3 with the same energy

C D density had similar columnar grain width, and sample P4
with the fastest scanning speed and smaller energy density
had finer columnar grains.

3.5. Mechanical properties of SEBM-fabricated
Inconel 718
The hardness of Inconel 718 fabricated by SEBM with the
parameters listed in Table 4 is shown in Table 5. It can be
Figure 10. Electron back-scattered diffraction-Inverse pole figure maps seen that the as-built samples without heat treatment had
on cross-section of as-built samples: (A) P1, (B) P2, (C) P3, and (D) P4. high hardness, because high temperature was maintained

A

B

C

D

Figure 11. Pole figures in the XY-plane: (A) P1, (B) P2, (C) P3, (D) P4.

Volume 1 Issue 4 (2022) 9 https://doi.org/10.18063/msam.v1i4.23