EML Batch 1 - NEQUISOL Experiment (EML Batch 1 - NEQUISOL Experiment) - 07.19.18

Overview | Description | Applications | Operations | Results | Publications | Imagery

ISS Science for Everyone

Science Objectives for Everyone
The NEQUISOL experiment focuses on the microstructure investigation and determination of the growth velocity of nickel-aluminum (Ni-Al) and aluminum-copper (Al-Cu) samples. During the melting cycles, the growth velocity as a function of undercooling will be investigated. The nucleation is triggered by a needle, and the growth velocities are determined by videos obtained with a High Speed Camera.
Science Results for Everyone
Unusual crystals form under just the right conditions. Investigators of the European Space Agency (ESA) discovered that when melted metals are cooled down in extremely low temperatures and kept away from surfaces, the dendrites of crystals grow very fast. In addition, a higher concentration of the element in the metal (i.e., Aluminum) leads to different dendrite growth characteristics. These results suggest that measurements in microgravity are important to understand how solidification of metals take place.

The following content was provided by Daniela Voss, and is maintained in a database by the ISS Program Science Office.
Information provided courtesy of the Erasmus Experiment Archive.
Experiment Details

OpNom:

Principal Investigator(s)
D. Herlach, Germany

Co-Investigator(s)/Collaborator(s)
Charles-Andre Gandin, Ph.D., Ecole de Mines de Paris, ARMINES-CEMEF (CETSOL), 6904 Sophia Antipolis, France
A. Garcia-Escorial, England
H. Henein, Canada

Developer(s)
Astrium GmbH, Bremen, Germany

Sponsoring Space Agency
European Space Agency (ESA)

Sponsoring Organization
Information Pending

Research Benefits
Information Pending

ISS Expedition Duration
March 2014 - September 2014; March 2015 - September 2015

Expeditions Assigned
39/40,43/44

Previous Missions
Information Pending

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Experiment Description

Research Overview
NEQUISOL focuses on the microscopic structure of nickel-aluminium and aluminium-copper alloys as they form around a needle inserted when they are in liquid form. The alloys grow like sugar crystals on a stick, and scientists assess the speed of the alloy growth in microgravity.

Description
Information Pending

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Applications

Space Applications
Industry partners to the projects seek to optimize ground processes, and have a direct interest in the knowledge that is gained from the experiments. This can, in turn, find its way into the development of new light-weight, high-performance structural materials for space applications.

Earth Applications
Investigations carried out with the Electro-Magnetic Levitator (EML) provide both reference data on thermophysical properties and microstructure formation for the same metallic alloy samples. (The microstructure in an alloy influences its characteristic properties such as strength, flexibility and resistance to fatigue). This information is of importance for feeding accurate data into current numerical models on one side, and also testing these models aiming to predict the solidification profile and related microstructure formation in the alloy samples. This concerns structural steels, magnetic materials, intermetallic materials, glass forming metallic alloys etc.

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Operations

Operational Requirements and Protocols
After container installation by crew, all activities are fully commanded by ground. Sample processing is executed during crew sleep, with continuous Ku and S band coverage so that micro-g-level and vibrations are known. One run per sample, with several melting cycles. Exact number of melting cycles for this experiment is still to be determined.
Samples to be returned:

  1. Al40Ni60
  2. Al70Ni30
  3. Ge
  4. Si50Ge50

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Decadal Survey Recommendations

CategoryReference
Applied Physical Science in Space AP9

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Results/More Information

To reveal how Aluminum-based metals change from a liquid to a solidified state, it is important to understand how nucleation (i.e., the formation of a new structure via self-assembly) and growth of crystals take place. When temperatures reach a point below freezing (i.e., undercooling) and the formation of crystals along container walls is completely avoided, solids of different physical and chemical properties can form.
 
NEQUISOL* is a project funded by the European Space Agency (ESA). Solidification used containerless processing and it was examined under Earth-gravity (1g) and microgravity (μg) conditions. Microgravity was mimicked in multiple ways. One, by the free fall of small droplets during atomization of a spray of droplets; two, by individual drops in a drop tube; three, by electromagnetic levitation of drops during parabolic flights; and four, by using the electromagnetic levitator facility aboard the International Space Station (ISS).
 
For Aluminum-based alloys, the dendrite growth velocity increased with undercooling in a stage by stage manner. An increase of Aluminum concentration by 5% lead to a change in dendrite growth characteristics. However, growth velocity decreased at undercoolings that were less than 175K. Once the growth velocity passed a minimum, it increased with rising undercooling. If the concentration of Aluminum was further increased, the minimum was shifted toward higher undercoolings.
 
Results demonstrated that solidification and microstructure of metals is strongly influenced by changes in mass and heat transport for experiments conducted under Earth-gravity (1g) conditions. These effects can be eliminated by analogous experiments conducted in microgravity, as shown by the dendrite growth velocity of undercooled aluminum-based alloys. Thus, it appears that measurements in microgravity are essential to quantitatively verify crystallization velocities in solidification models.

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Results Publications

    Herlach DM, Burggraf S, Galenko P, Gandin C, Garcia-Escorial A, Henein H, Karrasch C, Mullis A, Rettenmayr M, Valloton J.  Solidification of undercooled melts of Al-based alloys on Earth and in space. JOM Journal of the Minerals, Metals and Materials Society. 2017 August; 69(8): 1303-1310. DOI: 10.1007/s11837-017-2402-y.

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Ground Based Results Publications

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ISS Patents

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Related Publications

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Related Websites

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Imagery