# Research Activity: Synthesis and Processing Science

Division: Materials Sciences and Engineering

Primary Contact(s): Tim Fitzsimmons (<Tim.Fitzsimmons@science.doe.gov>;
301-903-9830)

Bassem Armaly (<Bassem.Armaly@science.doe.gov>; 301-903-4062)

Team Leader: Robert Gottschall

Division Director: Iran Thomas

# Portfolio Description:

Synthesis and Processing Science addresses the understanding necessary
to extend from synthesis to the preparation of materials with desired
structure, properties, or behavior. This includes development of *in
situ* measurement techniques and capabilities to quantitatively
determine variations in the energetics and kinetics of growth and
formation processes on small length scales. It also includes matters
related to the shaping and forming of structural metals by deformation
processes, the packing and consolidation of ceramic particulates, the
preparation of thin films and semiconductor junctions with controlled
elemental dopant profiles, coating and surface modification processes
including but not limited to those involving charged particle beams
plasmas and lasers, and the joining or welding of metals, ceramics,
and/or dissimilar materials by plasma, electron beam, laser and other
techniques. The Materials Preparation Center (MPC) at the Ames
Laboratory is operated to further advance and capitalize on this
understanding to fabricate research grade materials and provide these
materials to the research community.

# 

# Unique Aspects:

• The Materials Preparation Center at the Ames Laboratory is operated
for the purposes of understanding and further developing innovative and
superior processes and for providing small quantities of unique,
research-grade materials that are not otherwise available to academic,
governmental, and industrial research communities.

• Through the Center of Excellence for the Synthesis and Processing of
Advanced Materials (CESYNPRO), coordinated, collaborative research
partnerships related to synthesis and processing of advanced materials
are promoted between DOE national laboratories, universities, and the
private sector.

-   Non-equilibrium processing methods are studied using advanced
    modeling techniques and experimental methods, including innovative
    real-time, *in-situ* techniques enabled by synchrotron radiation.

**Relationship to Others:**

This program refines, further develops, and applies analytical
techniques from other BES programs to the needs and opportunities of
this research activity. Projects evolve from this CRA to other CRAs,
e.g., Physical Behavior of Materials and Mechanical Behavior and
Radiation Effects as scientific questions evolve concerning the
dependence of the physical and mechanical behavior of materials on the
parameters of synthesis and processing. The structure and composition of
materials is also supremely dependent upon the parameters of synthesis
and processing, this activity is intimately linked with the Structure
and Composition CRA.

Through materials supplied by the Ames MPC, linkage is provided to the
Office of Biological and Environmental Research, the academic community,
the industrial community and international research institutions. In FY
2000 the MPC provided materials to 15 users at DOE laboratories, 4 at
other federal laboratories, 38 at universities, 119 at industrial
laboratories, and 35 at international universities and institutions.
Total orders totaled \$602K in FY2000. The MPC is currently working on a
\$150K order for the preparation of 24kg of LaNi~(5-x)~Sn~(x)~. This is
to assist the Jet Propulsion laboratory in fabricating a Joule-Thompson
cryocooler for the joint ESA-NASA PLANCK Mission scheduled for 2007.

Additional linkages within the Department of Energy are provided through
the Energy Materials Coordinating Committee and its subcommittees on
superconductivity, semiconductors and photovoltaics, structural ceramics
and metals. Interagency coordination is provided by participation in the
MatTec Communications Group on Metals, the MatTec Communications Group
on Structural Ceramics, the MatTec Communications Group on
Nondestructive Evaluation, and the Interagency Working Group on
Nanotechnology.

# 

# Significant Accomplishments:

This program has changed the way people understand and think about the
preparation of materials. Experimental, theoretical and computational
tools are developed and applied to advance the scientific understanding
of complicated thermodynamic and kinetic phenomena underlying processes
ranging from self-assembly to welding. In the welding area, a coupled
thermodynamic and kinetic model was developed to describe stability of
the principal phases in stainless steels. This knowledge has led to the
modification of the standard diagram used to choose welding electrode
compositions for stainless steels. Additional modeling work utilizing
massively parallel computers has permitted the linkage of macro- and
microscopic scale phenomena during the melting and solidification of a
weld. This permits simulation and visualization of weld microstructure
as a function of processing conditions, e.g. during the melting,
addition of new compounds, and resolidification that occurs during
welding. Experimentally, tracking of real-time phase transformations
that occur during weld solidification are made possible using
synchrotron radiation and provide invaluable data to support scientific
modeling and simulation and leads to better electrode design. The later
work received the 2001 Spararagen Award from the American Welding
Society. A current application in electrode design is the new
understanding of the consequences of \"self shielding\"\--that is
preventing adverse reactions with air through additions of aluminum or
other powders to the electrodes on compound (phase) stability leading to
understanding of potential changes in electrode composition on
properties of welded components. Recognitions include the two recipients
of the Warren F. Savage Award from the American Welding Society

In the self-assembly area, developing scientific understanding of
surfactant interactions with ceramic compounds and other materials,
including biological tissues, has permitted the growth of ordered porous
ceramic structures duplicating template structures from the nanoscale to
the macro scale. Uses of these templating techniques to prepare ceramic
duplicates of complex biological tissues are currently under study.

Specific achievements include:

-   Investigation of the physics of multilayer structures and the
    ability to fabricate artificial semiconductor structures has led
    unexpectedly to the development of a biological microcavity laser in
    which a single human cell acts an internal component of the laser.
    This work was recognized with a 1997 IR&D Award.

-   A rapid, efficient self-assembly process for making nanophase
    composites that mimic the complex construction of seashells was
    developed and it resulted in a strong and tough (crack resistant on
    impact loading) material.

-   Ceramic substrates were synthesized with tailored and regularly
    ordered nanoscale pore sizes of controlled shapes and sizes. It was
    then found that these substrates would remove deadly heavy metals
    such as mercury, lead and silver from water. Recognition included a
    1998 R&D Award. This work was co-funded with the DOE Office of
    Environmental Management.

-   A breakthrough in the fundamental understanding of the processing of
    ceramic aerogel films led to a new, non-toxic, low temperature and
    low-pressure process to produce such films in an environmentally
    benign manner. This discovery overcame the sixty-year barrier to the
    large-scale commercial utilization of these films, won the
    prestigious Iler Award of the American Chemical Society and was
    cited as an important discovery by the Wall Street Journal.

-   Established a Materials Preparation Center to provide outside
    researchers from academia, industry and government laboratories with
    research quality and quantities of unique, carefully controlled
    research-grade materials and crystals that would not otherwise be
    available. The following technologies were enabled by this Center:

    -   Lead free solder

    -   Magnetocaloric gadolinium-silicon-germanium alloys

    -   Recyclable lightweight automotive composite materials

    -   Terfenol-D which is a mangetostrictive alloy containing terbium,
        dysprosium, and iron that was developed at the Center and led to
        the spin-off of a new private sector company which now markets
        this material

-   Nanocrystalline neodymium-iron-boron magnet alloys with matching
    crystallite and magnetic domain sizes that won an IR&D 100 Award in
    1997.

-   Quasicrystal coatings produced by plasma-arc spray that have
    superior wear resistance and thermal insulation behavior coupled
    with reduced surface friction for potential thermal barrier wear
    resistant coating applications in aircraft-engine components.

-   A uniform three-dimensional coating process known as \"Plasma Ion
    Immersion Processing\" was improved so as to fabricate hard coating,
    such as diamond-like carbon, that exhibit low sliding friction and
    superior wear resistance. This process achieves a uniform
    implantation rate over a very large surface, a very high rate of
    implantation, and has the ability to produce a uniform thickness and
    quality coating over complex three-dimensional geometries, and is
    cost-effective. This achievement was recognized with an R&D 100
    Award in 1997.

-   A nanophase molecular template method was developed to synthesize
    films that exploit the dielectric properties of air to achieve
    ultra-low dielectric constants for the next generation of
    microelectronic devices and computers.

**Mission Relevance:**

This research supports the Department of Energy's overarching goals for
improved energy efficiency and protection of the environment. Specific
relevant applications include hard and wear resistant surfaces to reduce
friction and wear; high-rate, superplastic forming of light-weight,
metallic alloys for fuel efficient vehicles and other structures needed
in fuel-efficient land and air transportation applications;
high-temperature structural ceramics and ceramic matrix composites for
high-speed cutting tools, bearings, engines and turbines (to enable fuel
efficiency and low-pollutant emissions); ordered intermetallic alloys
for harsh applications (requiring heat, load, wear and corrosion
resistance), including engines and turbines (also to enable fuel
efficiency and low pollutant emissions); non‑destructive analysis for
early warning of impending failure and on-line flaw detection and
quality assurance during production; response of magnetic materials to
applied static and cyclical stress; and plasma, laser, and charged
particle beam surface modification to increase corrosion and wear
resistance; and welding and joining, including dissimilar and
non-metallic materials.

# 

# Scientific Challenges: 

Understanding the thermodynamics and kinetics of reaction of nanoscale
powders and nanoscale structures with each other and the elements of the
processing environment are critical to the preparation of larger
components. There are significant computational and experimental
challenges in understanding what is occurring so that the benefits of
nanoscale phenomena can be realized in larger scale components.
Derivative questions involving nanoscale powders include reversible
passivation, steric interactions during consolidation, and inhibition of
grain growth and recrystallization during processing.

While silicon-based structural ceramics are now being used in demanding
applications such as turbocharger rotors, fuel ignitors, and
high-performance bearings, commercial applications fully exploiting the
high-temperature load-bearing capacity and creep resistance of
high-temperature structural ceramics are yet to be realized. The
scientific challenges include a plethora of fundamental questions
concerning the structure and behavior of intergranular films (that are
frequently as thin as one atomic layer), the understanding of the
microstructures (particularly as influenced by processing), and the
mechanisms of toughening (resistance to brittle fracture).

One challenge for non-destructive evaluation is in developing
understanding that will enable quantitative and predictive methods that
will permit applications such as early warning of impending crack
formation, fracture or other failure. Another challenge is on-line
*in-situ* diagnostics coupled to a process controller so as to provide
absolute manufacturing quality assurance. The scientific challenges lie
both in improving the fundamental and quantitative understanding of
materials degradation phenomena, and in improving analytical methods to
probe changes at scales from atomic to microstructural. Novel methods
being explored involve the use of physical acoustics and positron
annihilation.

**Funding Summary:**

**Dollars in Thousands**

**[FY 2000]{.underline}** **[FY 2001]{.underline} [FY2002]{.underline}**

\$13,820 \$12,801 \$14,781

> **[Performer]{.underline} [Funding Percentage]{.underline}**
>
> DOE Laboratories 86.0%
>
> Universities 14.0%

**Projected Evolution:**

• Increased emphasis on understanding the opportunities and challenges
presented by nanoscale materials and by the processing of larger
components containing nanoscale materials.

• Science based understanding of advanced synthesis and processing
methods such as self-assembly, molecular-directed nanostructure
formation, and novel deposition methods will be investigated. This
understanding will be applied of to attain new structures and
compositions, to fabricate materials with new functionalities, and to
reduce the energy and environmental impact of processing.

• Processing research will be extended to include new ceramic,
intermetallic, and semiconductor materials and material structures,
including nanocrystalline materials, films, coatings, and crystals.
Analytical techniques and modeling will developed and applied to
determine and predict the relationship of synthesis and processing
parameters to structure, purity, deformability, residual stresses,
toughness, adhesion, and electronic and magnetic properties.

• Welding process models will be refined and extended to solidification
of aluminum alloys. The relationship of process conditions to
microstructure development in various steel welds will be studied by
real-time, *in-situ* x-ray diffraction enabled by synchrotron radiation.
Follow-on work in supercooling effects in welding. Determination of
residual stress distribution in welds and spatial distribution of
different phases in different locations of the weld heat-affected-zone.

• Processing capabilities of the Materials Preparation Center will be
expanded to provide intelligent process control and modeling and to
provide new innovative synthesis and processing techniques. Plans
include the use of a plasma-heated skull-melting furnace with
capabilities to cast or atomize materials. Follow on efforts in
microstructure-sensitive processing and providing real-time monitoring
of processing and correlation with process models.

• An understanding of interfacial interactions at the molecular level
will be developed, and their influence on molecular conformation and
ordering will be shown for evolving nanostructures. An understanding of
how short and long-range molecular forces mitigate the formation of
ordered amorphous structures will be extended to develop an
understanding of how biological systems control the formation of ordered
assemblages of crystalline nanoparticles.

04 February 2002