CSLM-2 Overview Chart
Coarsening in Solid-Liquid Mixtures - 3 (CSLM-3)
CSLM-3 (2012) Status
June 2012 – The Coarsening
in Solid-Liquid Mixtures-3 (CSLM-3) team is preparing six Sample Processing
Units to launch on SpaceX-2. The Principal Investigator Peter Voorhees
is preparing lead-tin dendrite samples for CSLM-3. The CSLM-3 materials
science experiment will launch on SpaceX-2 and be operated in the Microgravity
Science Glovebox while docked to the International Space Station, then
undock from ISS and return the samples to earth on SpaceX-2.
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Ground Based |
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Microgravity |
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Electronics
Control Unit (ECU) |
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ECU and SPU
inside the MSG on ISS |
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Sample Processing
Unit (SPU) |
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| Side view of the CSLM-2 hardware inside the Microgravity Science Glovebox (MSG) | |||
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| NASA astronaut Garrett Reisman works at the MSG located in the Columbus laboratory of the ISS with the CSLM-2 investigation | |||
CSLM-2R (2010) Status
Feb 10, 2011 – The CSLM-2R experiment successfully processed
the Low Volume Fraction samples within the Sample Processing Units
on board the International Space Station and the samples will be returned
the on Space Shuttle STS-133/Flight ULF-5.
June 8, 2010 – The CSLM-2R
experiment was launched on the Space Shuttle STS-131/Flight 19A on
April 5, 2010. This set of CSLM-2R samples are the Low Volume Fraction
set provided by the Principal Investigator Peter Voorhees. The CSLM-2R
operated on board the International Space Station on June 8, 2010 through
July 7, 2010.
R...
The Coarsening in Solid-Liquid Mixtures (CSLM) experiment is a materials science space flight experiment whose purpose is to investigate the kinetics of competitive particle growth within a liquid matrix. During coarsening, small particles shrink by losing atoms to larger particles, causing the larger particles to grow. In this experiment solid particles of tin will grow (coarsen) within a liquid lead-tin eutectic matrix. By conducting this experiment in a microgravity environment, a greater range of solid volume fractions can be studied, and the effects of convection present in terrestrial experiments will be negligible. The flight hardware consists of two separable pieces of equipment, the sample processing unit (SPU) and the electronic control unit (ECU).
Research Description
CSLM-2 samples are processed inside
the Sample Processing Unit (SPU), which has a large, cylindrical sample
chamber. After a sample is completed, pressurized water is pumped into
the chamber to quench the sample, cooling it for removal. This system
can quench the sample from 185C (the temperature required to initiate
coarsening in tin-lead (Sn-Pb) samples) to 120C in only 6 seconds.
The Electronics Control Unit (ECU) provides power and the software that
controls all stages of processing. Parameters and status are displayed
on the ECU's LCD screen. The ECU controls the temperature inside the
SPU sample chamber and monitors and records the sample's temperature.
The quenching stage can be initiated automatically or controlled manually
by the crew. A base plate attaches the SPU and ECU to the Microgravity
Science Glovebox (MSG) work volume floor.
CSLM-2 will be conducted inside the sealed MSG work volume. The crew must load and initiate each run. Quenching can be initiated manually. Data captured by the ECU is transferred to the MSG laptop for storage and downloading to the ground-based researchers. The samples are a mixture consisting of Sn (tin)-rich particles in a Pb-Sn liquid, a mixture that has a low sintering temperature and a high coarsening rate, making it perfect for studying Ostwald ripening.
Space Applications
In any mixture that contains particles of different
sizes, the large particles tend to grow while the smaller particles shrink
in a process called coarsening. Tiny oil droplets coalescing into a large
blob are one illustration, but the process occurs in solids as well.
Coarsening occurs on Earth during the processing of any metal alloy and
thus the coarsening process affects products from dental fillings to
turbine blades. Since the properties of an alloy are linked to the size
of the particles within the solid, coarsening can be used to strengthen
materials. This is the case with the majority of aluminum alloys used
commercially today. Conversely, if the coarsening process proceeds too
long the material can weaken. This occurs in jet turbine blades and is
one of the reasons why turbine blades must be replaced after a certain
number of hours of service. Thus developing accurate models of the coarsening
process is central to creating a wide range of new materials from those
used in automobiles to those used in space applications. Solid-liquid
systems are ideal systems to study this coarsening process. However,
gravity can induce particle sedimentation and thus hamper the studies
of coarsening in these mixtures on Earth. The microgravity environment
of the Space Station allows scientists to study the process of coarsening
with reduced interference from the sedimentation that occurs on Earth.
On Earth, materials that contain pores created and trapped during solidification degrade properties and cause a distinct weakening in the overall structure of the cast product. Determining what causes these problems will lead to the development of improved manufacturing processes for materials.
Previous Missions
CSLM-1, a precursor to CSLM-2, was conducted
on STS-83 and STS-94. CSLM-2 was conducted during ISS Increment 7
CSLM-2 operated 5 SPU's on ISS during Increment 16 in December 2007. CSLM-2
operated 3 SPU's on ISS during Increment 17 in April 2008.
Future Missions
The CSLM-2 SPU's that were operated on the ISS during Increment 16 and Increment 17 have been returned to earth on the Shuttle. The CSLM-2 Principal Investigator is currently analyzing the samples from the SPU's returned.
Coarsening in Solid-Liquid Mixtures -2 (CSLM-2) CSLM-2 (2008) Status
February 10, 2011 – The Principal Investigator
Peter Voorhees at Northwestern University has analyzed the CSLM-2
high volume fraction samples from the six successful SPU’s and
is writing a CSLM-2 Report to document the science results. Overview In any mixture that contains particles of different sizes, the large particles tend to grow while small particles shrink during a process called coarsening. Tiny oil droplets coalescing into a large droplet are one illustration, but the process occurs in solids as well. Coarsening occurs on Earth during the processing of any metal alloy and thus the coarsening process affects products from dental fillings to turbine blades. Since the properties of an alloy are linked to the size of the particles within the solid, coarsening can be used to strengthen materials. This is the case with the majority of aluminum alloys used commercially today. Conversely, if the coarsening process proceeds too long the material can weaken. This occurs in jet turbine blades and is one of the reasons why turbine blades must be replaced after a certain number of hours of service. Thus developing accurate models of the coarsening process is central to creating a wide range of new materials from those used in automobiles to those used in space applications. Results from CSLM-1 on MSL-1, while not conclusive or comprehensive, were sufficient to aid substantially in the development of a commercially available computer code from QuesTek Innovations LLC, called PrecipiCalcä, which is used in the design of new materials. In this way knowledge generated by spaceflight experiments is impacting the design of new commercially important materials. Solid-liquid systems are ideal systems to study this coarsening
process. However, gravity can induce particle sedimentation
and thus hamper the studies of coarsening in these mixtures
on Earth. The microgravity environment of the International
Space Station will allow us to study the process of coarsening
with reduced interference from the sedimentation that occurs
on Earth. We have shown that solid-liquid mixtures
consisting of Sn-rich particles in a Pb-Sn eutectic liquid
are ideal, and perhaps unique, systems in which to explore
the dynamics of the Ostwald ripening process. The high
coarsening rate in these systems permit accurate kinetic
data to be obtained and the thermo physical parameters necessary
to make a comparison between theory and experiment are known. However,
in a terrestrial environment experiments can be performed
only at the relatively high volume fractions of solid where
the presence of a solid skeletal structure prevents large-scale
particle sedimentation. Our past experiments on the ISS have
also employed high volume fractions of coarsening phase to
avoid what was expected to be deleterious g-jitter. The objective
of this project is to perform a microgravity experiment on
Ostwald ripening in solid-liquid mixtures using the low volume
fractions of coarsening phase that can be directly compared
to heretofore untested theories for coarsening in systems. The
spaceflight experiment will produce data that, for the first
time, can be compared directly to theory with no adjustable
parameters. This data will address the long-standing controversy
over the dependence of the coarsening rate of a two-phase
system on the volume fraction of coarsening phase. It will
also complete the experimental matrix of the original CSLM-II
experiment. |
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Project Management:
Contacts at NASA Glenn Research Center |
