538 Rafi dah Hasan et al. Procedia Engineering 10 2011 536–541
m [8
p su
st h
2
st T
a le
m m
w o
a
F
3
3 lo
s to
w
F m
microstructure 8, 9], where
phases presen ubsequent he
tudied and rep have not been
2. Material
SLM Ti-6A tructures in p
Technik GmbH a 35° angle to
ength being manufactured
micro-struts w were then poli
optical micros analysis mappi
Fig. 3. A 43 mm m
3. Geometry,
Fig 4a sho 35° to the po
ongitudinal cr imilar to the w
o the solid sta with heat treate
Fig. 4. a Optical manufactured SLM
e present. The the strength o
nt, while the eat treatment.
ported, with a resolved in pr
Al-4V micro- previous rese
H Co., Germ the horizonta
limited to 43 SLM Ti-6Al
were prepared shed followin
scopy and SE ing.
micro-strut of SLM
Microstructu
ows the circu owder bed, di
ross-section o welded structu
ate transforma ed Ti-6Al-4V
l microscopic vie M Ti-6Al-4V sing
e effect of mi of SLM Ti-6A
microstructu In this pape
an objective o revious resear
struts were p arch [7], whi
many. As the l, the single st
3 mm by th l-4V micro-st
by hot-moun ng a standard m
EM, incorpora
M Ti-6Al-4V ma
ure and Elem
ular cross-sect iameter appro
of a micro-stru ure of titanium
ations that oc V [10].
w of circular cro gle strut built at 3
icrostructure o Al-4V produc
ure varied w r, the micros
of clarifying th rch work.
produced from ich was Titan
micro-struts i truts were ma
e manufactur trut. For mic
nting in condu metallurgical
ated with ele
anufactured at the
ment Analysis
tion of an as-m oximately 380
ut, with micr m alloy. Need
cur on coolin
oss-section; b M 35° angle laser be
on behavior i cts varied wit
ith the SLM structure of th
he SLM Ti-6A
m the same p nium Powder
in the BCC ar anufactured at
ring process. crostructure st
uctive resin u procedure, be
ectron dispers
University of Liv
of Micro-str
manufactured m. The o
o-voids withi dle like structu
ng. This struct
Microstructure of eam at 200 W lase
Dendritic st
s also implied th the micros
M process par he SLM Ti-6
Al-4V micro-
powder mater r Grade 5 AS
rchitecture of a 35° build a
Fig 3 show tudies, metall
sing a 20 mm efore being etc
ive spectrosc
verpool
200W
rut
SLM Ti-6Al optical microg
in the strut, an ures are prese
ture is differe
f longitudinal sect er power and 100
100 tructures
micro Ͳ
voids
d in other rese tructure form
rameters used Al-4V micro
lattice failure
rial as the m STM produce
the micro-latt angle, with the
ws an image lurgical samp
m diameter m ched and obse
copy EDS f
X 1000 s
l-4V micro-str graph Fig 4b
nd a dendritic ent within the
nt to that nor
tioned; both figur 00
s laser exposu
ђm
b
earch work med and the
d and any -struts was
issues that
micro-lattice ed by TLS
tices was at e maximum
of the as- ples of the
mould. They erved under
for element
rut build at b shows a
c structure, grains due
rmally used
res are the as- ure time
Rafi dah Hasan et al. Procedia Engineering 10 2011 536–541 539
th
F 4V
sp T
st u
ra a
a p
th w
st c
p
F
Within the he material F
Fig. 5. A focused V micro-strut wit
Elemental a pectrum 2 th
These included tructures are
used in this SL ather than po
atmosphere is and within inte
precipitation in hat the dendri
weak point in trong as the
compared with present in thes
Fig. 6. The EDS p
microstructur Fig 5.
SEM image of d th 200W X 1000
analysis of th hey were rich
d relatively hi due to the cro
LM machine. owder prepara
carefully filte er-layer areas
n the solid sta ite formation
the micro-str weakest poin
h 373 HV tha e regions.
plot of spectrum 1
re were region
dendritic structure s
hese regions h in elements
igh amounts o oss contamina
It is likely t ation and ma
ered [11]. Sin these phases
ate and are lik affects the me
rut initiating c nt. It was fo
at the bulk of t
for elemental an
ns that althoug
e with indicated p
Fig 6, spectr not normally
of iron Fe an ation of the p
that this conta ay have come
nce most of th probably form
kely to form p echanical prop
cracking acro ound that the
the structure.
nalysis of as-recei
gh dendritic lo
points for spectru
rum 1 showe y found in Ti
nd chromium powder bed w
amination occ e from the po
hese dendritic m due to segre
part of the las perties as if th
oss the strut in ese structures
It has not yet
ived micro-strut c
ooked very di
um 1 and 2 in ele
ed that compa itanium Powd
Cr. It is lik with 316L stain
curred during owder feed sy
c structures w egation during
st liquid to fre hey are brittle
n that region, were signifi
been possible
confirmed with T
ifferent from
emental analysis
ared to the bu der Grade 5 A
kely, therefore nless steel wh
the manufactu ystem as the
were found at g freezing rath
eeze. It is also e or soft they w
, the strut onl icantly harder
e to determine
Ti-6Al-4V elemen
the bulk of
SLM Ti-6Al-
ulk Fig 7, ASTM [7].
e, that these hich is also
uring stage argon gas
boundaries her than by
o suspected will form a
ly being as r 419 HV
e the phases
nts
540 Rafi dah Hasan et al. Procedia Engineering 10 2011 536–541
F su
4
p th
e s
th th
e c
h re
st a
S
F sh
T
Fig. 7. The EDS uspected due to c
4. Heat Treatm
