This
work
studied
microstructural
evolution,
precipitate
behaviors,
and
micro-hardness
distribution
along
the
building
direction
of
direct
energy
deposited
IN718
alloy.
In
combination
with
digital
image
correlation
crystallographic
orientation
analysis,
plastic
deformation
fracture
mechanisms
coarse
columnar
grains
were
explored
in
detail.
The
solidification
structure
deposition
zone
(DZ)
grows
<001>
crystallography.
However,
become
wider
increasing
height.
cumulative
misorientation
angle
length
within
first
gradually
decreases
then
slows
down
to
~
0.07
°/mm
when
height
is
1.8
mm.
DZ
decreased
direction,
which
may
be
due
average
grain
width
primary
dendrite
arm
spacing,
as
well
reducing
volume
fraction
y''
+
y'
phases.
During
uniaxial
tensile
loading,
most
always
occurs
irrespective
lowest
hardness
HAZ.
nucleation
microvoids
ascribed
granular
Laves
phase
debonding
from
y
matrix.
number
distance
fracture,
attributed
strain
gradient
distribution.
EBSD
results
substantiated
that
near
surface
occur
severe
lattice
rotation,
leading
Kernel
each
interior
about
1°
4°.
conference,
Journal Year:
2025,
Volume and Issue:
unknown, P. 1 - 13
Published: April 6, 2025
Abstract
In
this
study,
we
investigate
the
effect
of
printing
parameters
on
mechanical
properties
UNS
N07718
alloy
and
optimized
are
used
to
print
AM
samples.
We
also
investigated
hydrogen
additively
manufactured
(AM)
718
compared
it
with
conventionally
(CM)
Electrochemical
charging
was
performed
both
CM
samples
achieve
comparable
content
in
samples,
which
further
measured
by
thermal
desorption
spectroscopy
(TDS).
Identically
charged
were
mechanically
tested
tensile
test
hardness
quantitatively
correlate
degradation
introducing
different
contents
into
A
combination
surface
characterization
techniques:
Scanning
Electron
Microscopy
(SEM),
Energy
Dispersive
X-ray
Spectroscopy
(EDX),
X-Ray
Diffraction
(XRD),
Backscatter
diffraction
(EBSD)
deployed
accurately
characterize
gain
an
improved
understanding
embrittlement
mechanism
718.
The
higher
presence
reduced
ductility
as-built
/
as-received
but
did
not
significantly
influence
response
materials.
Hydrogen-charged
exhibited
a
large
area
brittle
fracture
mode,
while
hydrogen-free
showed
ductile
morphology.
Journal of Alloys and Compounds,
Journal Year:
2023,
Volume and Issue:
976, P. 173181 - 173181
Published: Dec. 15, 2023
Additive
manufacturing
(AM)
is
well-known
for
its
capability
to
produce
and
repair
intricate
parts
e.g.,
Ni-based
superalloy
components
used
in
aero-engine
applications.
However,
a
comprehensive
understanding
of
the
microstructure
evolution
link
properties
remains
elusive,
with
gaps
through-process
γ
grains,
γ',
γ'',
δ,
other
phases
response
thermal
cycling.
The
outstanding
challenge
here
observe
these
transformations
dynamically
during
3D
printing
process,
as
this
usually
requires
complex
in-situ
measurements.
Here
we
apply
different
approach
systematically
reveal
impact
cycling
on
solid-state
IN718,
via
combination
physical
simulations
thermo-kinetic
modelling.
We
replicate
cycles
IN718
experiences
laser
directed
energy
deposition.
Solid-state
are
shown
have
minor
effects
grain
morphology
due
short
holding
times
at
critical
temperatures,
however,
they
do
induce
plastic
strain
accumulation.
Significantly,
show
how
influences
γ",
δ
phases.
While
high
initial
peak
temperatures
inhibit
precipitation
phases,
prolonged
gradually
decreasing
promotes
their
precipitation.
phase
forms
along
twin
boundaries,
while
both
γ'
γ"
predominantly
precipitate
Nb-enriched
regions,
causing
heterogeneities
hardness.
Our
results
underpin
suitability
replicating
AM,
highlighting
potential
tool
advance
current
limited
property
evolution.
