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A D V A N C E D
M A T E R I A L S
&
P R O C E S S E S |
M A Y
2 0 1 6
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the microstructure with orientation
information. The method has been
used on Ti, Ni, Zr, and Al alloys.
Researchers at The Ohio State
University, Columbus, are using STEM
to characterize the α/β interface in
three different types of α precipitates
in Ti-5Al-5V-5Mo-3Cr. High-angle annu-
lar dark-field (HAADF) imaging iden-
tifies and quantifies the terrace and
ledge structure along the α/β inter-
face. This provides valuable insight
into the influence of the α/β interface
on mechanical properties, which can
be used to develop predictive models
to optimize processing. Microtextured
regions (MTRs) have a deleterious effect
on dwell fatigue response for various
near α and α+β titanium alloys. Robust
microtexture characterization meth-
ods that include size, hard/soft grain
orientations, and misorientations were
developed.
One method uses DREAM-3D
(Hampshire, UK) open-source soft-
ware to extract critical MTR metrics
from representative samples. Data is
used to create statistically equivalent
synthetic microstructures to assess
the probability of certain microtexture
combinations that could manifest a
given volume of material (Fig. 3). After
identifying critical microstructure and
texture combinations, synthetic vol-
ume elements created in DREAM-3D are
analyzed in a finite element analysis
package with a linked crystal-plasticity
code to assess damage accumulation.
Overall, the conference was well
received with technical discussions
in just about every technology area
including extraction, melting, thermo-
mechanical processing, machining,
welding, additive manufacturing, and
more. All countries active in the tita-
nium industry were well represented.
Note: TIMETAL54M and ATI 425
are registered trademarks of Timet and
Allegheny Technologies Inc., respec-
tively. RTI-XPT is a trademark of RTI
International Metals Inc. CermeTi-10
is a registered trademark of Dynamet
Technology Inc. ~AM&P
References
1.
ITA 2014 Proceedings, ITA 2014
Proceedings.
Fig. 3 — Synthetic volume element created in DREAM-3D.