Bill Boettinger
- Dr. William J. Boettinger, NAE
- NIST Fellow
- Metallurgy Division
- Materials Science and Engineering Laboratory
- NIST
- Gaithersburg, MD 20899
- 301-975-6160
- [email protected]
Research Interests
- Application of Phase-Field Methods to Solidification,
Electrochemisty
and
Other Processes
- Reactive Wetting. Pb-free Solder. Sn whisker growth from
electrodeposits
- Prediction of Solidification Path of Multicomponent Alloys
- Modeling of DTA Response
- Multicomponent/Multiphase Diffusion / 3-D Kirkendall Effect
- Crystal growth and thermodynamic aspects of nanowires
- New- Hydrogen Storage in Laves phases
Phase-Field Calculations
Solidification work has been done in collaboration with Jim Warren in
the
Metallurgy Division and Jeff McFadden in the Center for Computational
&
Applied Mathematics at NIST, as well as Adam Wheeler at the University
of Southhampton (U.K.) This model differs from more traditional
approaches
to solidification, in that the liquid-solid interface is assumed to be
diffuse. This permits simulation of solidification pattern without
"tracking"
the position of the liquid-solid interface. Work on solute trapping has
also been completed.
Click on the Figure below to see movies (phase-field simulations) of
Nickel-Copper solidification done in collaboration with Jim Warren.
The Phase-Field approach has also been applied to modeling the
equilibrium
and dynamics of planar electrochemical interfaces. This work has been
done
in collaboration with with Jon Guyer of the Electrochemical Processing
Group of the NIST Metallurgy Division. Equilibrium
Kinetics Animated
graph (concentrations, charge and potential) during initial transient
and
steady state alloy plating
Solder and Solder Finishes
Phase diagrams of selected Pb-free solder systems are under
investigation
(click
here). The location of the ternaty eutectic in Sn-Ag-Cu alloys has
been determined. See "Experimental and Thermodynamic Assessment of
Sn-Ag-Cu Solder Alloys,” K.-W. Moon, W. J. Boettinger, U. R. Kattner,
F. S. Biancaniello and C. A. Handwerker, J. Electronic Materials, 29
(2000), pp. 1122 - 1136.
Soldering involves a reaction of Sn with the base metal being
soldered. The diffusion processes involved in a simple reactive wetting
problem disolution of the substrate only) were studied to determine how
the triple junction motion is coupled to this reaction. See
"Modeling Reactive Wetting”, J. A. Warren, W. J. Boettinger & A. R.
Roosen, Acta Mater., 46 (1998) 3247. Work is contining use a
phase fffield approach.
Sn whisker growth has become a reliability issue with the convesion
to Pb-free surface finishes to maintain soldeability on electronic
components. Stresses in electrodeposited Sn has been
measured with a cantilever
beam technique with a focus on understanding the mechanisms of whisker
growth. At paper on NIST whisker research is available (click
here). Current work involves measurement of stress in Sn
electrodeposits using x-ray diffraction
Solidification Path
Completed research with industry includes an effort to improve the
modeling
of castings through the NIST "Consortium on Casting of Aerospace
Alloys."
Efforts here were focussed on describing the solidification path for
multicomponent
Ni-base superalloys. This approach utilizes a thermodynamic calculation
of the phase diagram information needed for the solidification kinetic
models. Much of this work is described each May/June at a
Solidification course in Les Diablerets in Switzerland that is
sponsored by EPFL (M. Rappaz).
DTA
To assist users of Differential Thermal Analysis understand the
response
of the instrument to the melting and freezing of alloys, a
MathematicaTM
script & description of published work with Ursula Kattner
can
be downloaded
. A "Best Practice Guide" on the subject is completed. Click
here.
Multicomponent/Multiphase Diffusion
Research has been focused on modeling transient liquid phase bonding
(w/ Carelyn Campbell) of Ni-Al with Ni-B. The thermodynamics of the
Ni-Al-B
system has been developed using the Calphad method. The diffusion
behavior
has been modeled with the code, Dictra. Three dimension effects
encountered
with the Kirkendall effect has been treated. See publication list. Click
here to see the activities of the NIST Diffusion Working Group
Nanowires
Recent research with Albert Davydov of the NIST Metallurgy Division is
focused assessing metal-semiconductor phase diagrams to provide
rationale
for selecting VLS growth catalysts and electrical contact metals for
ZnO
and GaN nanowires.
Publications
Privacy
Statement/Security Notice
Technical inquiries: [email protected]
Center for Theoretical and Computational Materials Science
National Institute of Standards & Technology
Building 223, Room A311
Gaithersburg, MD 20899 Tel: (301)975-5708 FAX:(301)975-4553
NIST
General NIST inquiries:
Public inquiries:
(301)975-NIST (6478)
(301)975-8295
