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Additive Manufacturing
of Titanium Alloys
T
itanium alloys are among the most im-
portant advanced materials and are key
to improved performance in both aero-
space and terrestrial systems, due to an excel-
lent combination of specific mechanical
properties and outstanding corrosion behav-
ior
[1]
. However, widespread use is constrained
by the high cost of titanium alloys compared to
alternative materials
[1]
.
The high cost of producing conventional
titanium components has spurred numerous
investigations into potentially lower cost
processes, including powder metallurgy (PM)
near-net-shape techniques such as additive
manufacturing (AM)
[1]
. This article reviews
AM with an emphasis on the “work horse” ti-
tanium alloy, Ti-6Al-4V. AM is receiving sig-
nificant
attention
from
numerous
organizations including the U.S. Navy, as it
envisions use aboard carriers with parts able
to be rapidly fabricated for immediate use by
battle groups
[2]
. Various approaches to AM,
along with examples of components made by
different AM processes, are presented. The
microstructures and mechanical properties of
Ti-6Al-4V produced by AM are also dis-
cussed and compare well with cast and
wrought products. Finally, the economic ad-
vantages of AM compared to conventional
processing are presented.
Additive manufacturing overview
All AM technologies are based on the
principle of slicing a solid model into multiple
layers and building the part up layer by layer
following the sliced model data. Following
ASTM classification, AM technologies for
metals can be broadly classified into two cat-
egories: directed energy deposition and pow-
der bed fusion (Table 1). Several technologies
fall under each category as branded by differ-
ent manufacturers. While powder bed fusion
B. Dutta*
DM3D Technology LLC
Auburn Hills, Mich
.
F.H. (Sam) Froes,
FASM*
Titanium industry
consultant
Tacoma, Wash.
ADVANCED MATERIALS & PROCESSES •
FEBRUARY 2014
18
Although the
widespread
use of titanium
alloys is
constrained by
high costs,
powder
metallurgy
techniques
such as
additive
manufacturing
represent an
economical
approach to
fabricating
titanium
components.
TABLE 1 — ADDITIVE MANUFACTURING TECHNOLOGIES
FOR PROCESSING TITANIUM AND ITS ALLOYS
AM Category
Technology
Company
Description
Directed Energy
Direct Metal
DM3D Technology
Laser and metal
Deposition (DED)
Deposition (DMD)
LLC (formerly POM powder used for
Group)
melting and depositing
with a patented closed
loop process.
Laser Engineered Net Optomec Inc.
Laser and metal
Shaping (LENS)
powder used for
melting and depositing.
Direct Manufacturing Sciaky Inc.
Electron beam and
(DM)
metal wire used for
melting and depositing.
Powder Bed
Selective Laser
3D Systems Corp.
Laser and metal
Fusion (PBF)
Sintering (SLS)
(acquired Phenix
powder used for
Systems)
sintering and bonding.
Direct Metal Laser
EOS GmbH
Laser and metal
Sintering (DMLS)
powder used for
sintering, melting, and
bonding.
Laser Melting (LM)
Renishaw Inc.
Laser and metal
powder used for
melting and bonding.
Laser Melting (SLM)
SLM Solutions
Laser and metal
GmbH
powder used for
melting and bonding.
LaserCUSING
Concept Laser
Laser and metal
GmbH
powder used for
melting and bonding.
Electron Beam
Arcam AB
Electron beam and
Melting (EBM)
metal powder used for
melting and bonding.
*Member of ASM
International