DEvice for the study of Critical LIquids and Crystallization - Directional Solidification Insert (DECLIC-DSI) - 03.16.16
DEvice for the study of Critical LIquids and Crystallization (DECLIC) is a multi-user facility utilized to study transparent media and their phase transitions in microgravity onboard the International Space Station (ISS). The Directional Solidification Insert (DSI) portion of the DECLIC multi-user facility experiment will study a series of benchmark experiments on transparent alloys that freeze like metals under microgravity onboard the International Space Station (ISS) using SCN (succinonitrile-a transparent organic substance in the liquid state that is used to study the phenomena related to solidification processes) based alloys. The DSI insert will be installed for the second run of the three series of DECLIC experiments. Science Results for Everyone
Pardon me, your liquid-solid interface is showing. Studying the process of solidification can improve our understanding of metallurgical processes, which are important in the design and processing of materials. In a series of experiments in microgravity using transparent alloys that freeze like metals, researchers recorded images of the microstructures that form at the liquid-solid interface. As the interface microstructure governs the mechanical and physical properties of the solidified material, understanding its formation enables the design of improved materials. During one experiment, consisting of a solidification of a long cylindrical sample, researchers captured about 7,000 images to follow the formation and evolution of the microstructure. The results highlighted the strong influence of the interface shape, as it appeared that it modifies the dynamics of formation and evolution of the microstructure. The shape especially affects the characteristic size of cells and dendrites that form the microstructure. One of the most striking results is also the unprecedented observation of oscillating patterns of cells: for some specific growth conditions, the cells appear to expand and contract periodically, and the pattern of this oscillation depends in part on the overall structure that the cells form. Experiment Details
Nathalie Bergeon, Ph.D., Paul Cézanne University Aix-Marseille III, Marseille, France
Sebastien Barde, Centre National d‘Etudes Spatiales (CNES), Paris, France
Nathalie Mangelinck-Noel, Ph.D., Aix-Marseille Universite´, Marseille, France
Bernard Zappoli, Centre National d'Etudes Spatiales (CNES), Toulouse, France
Centre National d'Etudes Spatiales, Toulouse, France
Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)
Human Exploration and Operations Mission Directorate (HEOMD)
ISS Expedition Duration 1
October 2009 - May 2012
Previous ISS Missions
For supercritical fluids (HTI, ALI), DECLIC is a continuation of one conducted aboard the Mir Space Station and the Space Shuttle. For solidification of transparent model alloys, DECLIC-DSI is the first mission in space environment, following series of intensive studies on ground.
- DECLIC-DSI (DEvice for the study of Critical LIquids and Crystallization-Directional Solidification Insert) involves the in situ and real-time observation of the microstructures that form at the liquid-solid interface when transparent materials solidify. This will make it possible to simulate metallic alloys, with the advantage of recording the dynamical formation and selection of the microstructures. Another practical advantage is that only images will be transferred to the ground instead of heavy samples for post mortem characterization since the transport into orbit and the return to Earth greatly increases the cost of missions.
- The study of cellular and dendritic (growth shape with tree-like side branches like snowflakes) solidification patterns associated with DECLIC-DSI provides an opportunity to gain an insight into the general problem of pattern formation since the three-dimensional pattern evolution dynamics can be quantitatively studied under well-defined conditions.
- The DECLIC-DSI experiment intends to provide a better understanding of the relationship between micro- and macrostructure formation during solidification processes. For the first increments on ISS, DECLIC-DSI contains a cell filled with a dilute SCN - Camphor alloy, which will be moved from a hot zone to a cold zone at various speeds and temperature gradients.
Directional Solidification Insert (DSI) involves the study of directional solidification in relation to transparent model alloys. This involves investigating the birth and growth of morphological instabilities at the solid-liquid interface and the effects of coupling between the solidifying interface and the convection. By observing these phenomena in a microgravity environment, it will be possible to refine the theoretical models and numerical simulation predictions, which will ultimately result in the improvement of the industrial ground-based material development processes. The ambition of the reduced-gravity experiments on ISS, which will consist of directional solidification of SCN-based bulk alloys in the Directional Solidification Insert (DSI) of the DECLIC facility with a systematic variation of the process parameters, is to obtain benchmark data on cellular and dendritic microstructure formation under diffusive transport conditions. Precise measurement of interface shape and geometrical characterization of cellular and dendritic patterns, as well as of individual cell or dendrite will be carried out as a function of time for different values of composition, growth rate and temperature gradient. These measurements will be used in combination with modeling and numerical simulations of the temperature field to establish the physics that govern the dynamics of interface pattern selection, and to quantitatively determine the conditions for the planar to cellular and cellular to dendritic transitions. Optical observations of the solidification front will be done either directly or by interferometry (imaging using the interference fringes resulting from the recombination of reference and object light beams issued from the same coherent source) with the cartridge placed in one arm of a Mach-Zehnder interferometer (a device used to determine phase shifts caused by the solidifying sample which is placed in the optical path of the object beam).
The DECLIC facility provides power, communications, command/control, data storage, and multiple, flexible optical capabilities in support of each experiment. DECLIC-DSI involves investigating the birth and growth of morphological instabilities and the effects of coupling between the solidifying interface and the convection. By observing these phenomena in a microgravity environment, it will be possible to refine the theoretical models and numerical simulation predictions, which will ultimately result in the improvement of the industrial ground-based material development processes.
DECLIC-DSI will establish the fundamental physics that govern the formation and selection of solidification patterns. This will provide an opportunity to gain an insight into the general problem of pattern formation, as solidification patterns are recognized to be similar to those forming in many other branches of science.
In order to adjust the parameters and optimize the scientific results, some data must be downloaded in real-time or near real-time. For complete analysis by the scientists, the data will be retrieved either via telemetry in deferred time, or via the removal of hard disks which will be brought back by the crew. The DECLIC-DSI Experiment is scheduled for a period of 75 days.
The ISS crew will install the DECLIC hardware into an EXPRESS Rack in the U.S. Laboratory. The DSI insert will be installed into DECLIC for the second run of the series of DECLIC experiments. Crew participation is not required during the run(s). Tape change-out will be required by the crew at some stage during the run(s).
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The Directional Solidification Insert (DSI) is dedicated to in situ and real time observation of the surface of the boundary between a solid and a liquid. The boundary, or interface, is created as the alloy becomes solid. The alloy is contained within a crucible, which the scientist move from a relatively hot area of a furnace, to a relatively cold area.
The French Space Agency (CNES) developed the DECLIC device (Dispositif pour l'Etude de la Croissance et des LIquides Critiques) as part of a joint project with NASA. DSI was launched into space in December 2009, and six runs of two to three weeks each were performed from April 2010 to April 2011. The DSI was then brought back to the ground, and two runs of two weeks each were performed at the CNES center with similar control variables to the experiments in microgravity. This was to address the influence of convection.
A series of experiments were performed, each with varying conditions of solidification, such as the pulling rate and thermal gradient. Each solidification experiment generates about 7000 images. These are analyzed to extract quantitative information of the interface features (Bergeon 2011). The microgravity environment provided the conditions to get quantitative benchmark data: homogeneous patterns corresponding to homogeneous values of control parameters along the whole interface were obtained (Bergeon 2011; Ramirez 2011).
The sequence of microstructure formation was analyzed, as well as the evolution of the primary spacing, which is one of the most important pattern characteristics. The analyses showed how influential the shape of the interface (concave or convex) was on the mechanisms of spacing selection (Bergeon 2015). This curvature is unavoidable when bulk samples are solidified, so that is one parameter to take into account in analysis and simulations.
Another interesting point to study during solidification is the motion of the liquid-solid interface in the thermal field. This motion is mainly due to a change of its temperature, which itself is due to an evolution of the solute concentration in the liquid and in the solid. The interface motion reflects the distribution of the alloy components in the final product. The details of such analyses can be found in Mota 2015. The comparison of space and ground experiments pointed out a major effect of convection on the macro-segregation profile. It also appeared that for some specific conditions, such as low solidification rates, the effect of residual convection is visible in the front motion during microgravity experiments. This suggests that for these specific conditions, the effective level of reduced gravity on board the ISS is not low enough.
The favorable conditions provided by microgravity allowed to observe for the very first time the dynamics of extended oscillating cellular patterns (Bergeon 2013). Cells form an array as the alloy becomes solid. For some specific growth parameters, they appear to expand and contract rhythmically similarly to way that lungs breathe, albeit with a period ranging from tens of minutes to more than an hour. The experiments further reveal that all the cells in the array do not expand and contract at unison. The phase strongly correlates with the structure of the array. In local ordered regions of the array that exhibit a honeycomb-like structure, cells belonging to three distinct sub-lattices of the hexagonal lattice breathe out of phase with each other. Cells on one sub-lattice repress the growth of neighboring cells on the other sub-lattices. As a result, cells on each sub-lattice take turn breathing in and out with a 120-degree phase shift between breathing cycles of cells on the different sub-lattices. In contrast, in disordered regions, cells oscillate with seemingly random phases. Furthermore, large amplitude breathing oscillations can cause a cell elimination or a cell splitting into two daughter cells, which may both survive or not. This regenerative and elimination process can in turn have a profound influence on the array structure. An extensive phase-field study of these oscillatory breathing modes is presented in Tourret 2015.
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Mota FL, Bergeon N, Tourret D, Karma A, Trivedi R, Billia B. Initial transient behavior in directional solidification of a bulk transparent model alloy in a cylinder. Acta Materialia. 2015 February; 85: 362-377. DOI: 10.1016/j.actamat.2014.11.024.
Tourret D, Debierre J, Song Y, Mota FL, Bergeon N, Guerin R, Trivedi R, Billia B, Karma A. Oscillatory cellular patterns in three-dimensional directional solidification. Physical Review E. 2015 October 7; 92(4): 042401. DOI: 10.1103/PhysRevE.92.042401. PMID: 26565251.
Mota FL, Bergeon N, Tourret D, Karma A, Trivedi R, Billia B. Effect of thermal drift on the Initial transient behavior in directional solidification of a bulk transparent model alloy. Hoboken, NJ: TMS 2016: 145th Annual Meeting & Exhibition: Supplemental Proceedings; 2016.
Bergeon N, Tourret D, Chen L, Debierre J, Guerin R, Ramirez A, Billia B, Karma A, Trivedi R. Spatiotemporal dynamics of oscillatory cellular patterns in three-dimensional directional solidification. Physical Review Letters. 2013 May 31; 110(22): 226102. DOI: 10.1103/PhysRevLett.110.226102. PMID: 23767735.
Ramirez A, Chen L, Bergeon N, Billia B, Gu J, Trivedi R. In situ and real time characterization of interface microstructure in 3D alloy solidification: benchmark microgravity experiments in the DECLIC-Directional Solidification Insert on ISS. IOP Conferene Series: Material Science and Engineering. 2012 January 12; 27(1): 012087. DOI: 10.1088/1757-899X/27/1/012087.
Bergeon N, Mota FL, Chen L, Tourret D, Debierre J, Guerin R, Karma A, Billia B, Trivedi R. Dynamical microstructure formation in 3D directional solidification of transparent model alloys: in situ characterization in DECLIC Directional Solidification Insert under diffusion transport in microgravity. IOP Conferene Series: Material Science and Engineering. 2015 June 11; 84: 012077. DOI: 10.1088/1757-899X/84/1/012077.
Pont G, Barde S, Bioulez P, Blonde D, Zappoli B, Garrabos Y, Lecoutre C, Beysens DA, Bergeon N, Billia B, Mangelinck-Noel N, Ramirez A, Trivedi R. DECLIC, first results on orbit. 61st International Astronautical Congress, Prague, Czech Republic; 2010 January 10 pp.
Bergeon N, Ramirez A, Chen L, Billia B, Gu J, Trivedi R. Dynamics of interface pattern formation in 3D alloy solidification: first results from experiments in the DECLIC directional solidification insert on the International Space Station. Journal of Materials Science. 2011; 46: 6191-6202. DOI: 10.1007/s10853-011-5382-2.
Ground Based Results Publications
Cambon G, Zappoli B, Barde S, Duclos F, Lauver R, Marcout R, Raymond G, Beysens DA, Garrabos Y, Lecoutre C, Billia B, Bergeon N, Mangelinck-Noel N. The DECLIC program developments status. 55th International Astronautical Congress, Vancouver, Canada; 2004 October 4 11 pp.
Pont G, Barde S, Blonde D, Zappoli B, Garrabos Y, Lecoutre C, Beysens DA, Hicks MC, Hegde UG, Hahn I, Bergeon N, Billia B, Chen L, Ramirez A, Trivedi R. DECLIC, soon two years of successful operations. 62nd International Astronautical Congress, Cape Town, South Africa; 2011 October 3-7 12 pp.
Pont G, Barde S, Zappoli B, Garrabos Y, Lecoutre C, Beysens DA, Hicks MC, Hegde UG, Hahn I, Bergeon N, Billia B, Trivedi R, Karma A. DECLIC, now and tomorrow . 64th International Astronautical Congress, Beijing, China; 2013 9 pp.
Pont G, Belbis O, Burger H, Bornas N. DECLIC Operations and Ground Segment an Effective Way to Operate a Payload in the ISS. 63rd International Astronautical Congress, Naples, Italy; 2012
Marcout R, Raymond G, Martin B, Cambon G, Zappoli B, Duclos F, Barde S, Beysens DA, Garrabos Y, Lecoutre C, Billia B, Bergeon N, Mangelinck-Noel N. DECLIC : A facility to investigate fluids and transparent materials in microgravity conditions in ISS. 57th International Astronautical Congress, Valencia, Spain; 2006 October 6 13 pp.
DECLIC: French experiment on ISS reveals new insights
Ames Laboratory senior metallurgist Rohit Trivedi will be studying how crystals, such as these nickel-based superconductors, grow in low gravity experiments on board the International Space Station. Image courtesy of USDOE's Ames Laboratory.
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