Main Results and Achievements | ЛЭМПНМ

Лаборатория электромагнитных методов производства новых материалов

Main Results and Achievements

The main results and achievements of the Laboratory of Electromagnetic Field-Assisted Methods for Processing of Novel Materials over the period of "October 2011 - October 2013"

 

The main achieved objective of the project is the establishment of the unique research and educational university unit in the field of electromagnetic methods of consolidation of new materials, including structural and functional nano-materials, which came true.

The object of research is the advanced technologies of spark plasma sintering, microwave sintering, high-voltage electric-discharge compaction, and magnetic pulse consolidation of powders. The availability of the laboratory allows MEPhI to actively participate in projects related to the creation of new materials (such as the Russian-Ukrainian joint research project "Development of Methods of Processing and Consolidation of Composites Based on Iron and Titanium Carbides and Borides by Highly Concentrated Energy Fluxes" (grant of the Russian Foundation for Basic Research and of the Ukraine National Academy of Sciences, 2012 - 2013); "Innovation-Oriented Program of Joint Research with Specialized Universities" established by the State Corporation Rosatom; a joint program between MEPhI and the Massachusetts Institute of Technology to create a Center for Science, Innovation and Education as a unit of the Skolkovo Institute of Science and Technology (Skoltech); etc.), followed by the transition of the research products to the industry. The established Laboratory provides also a unique opportunity to develop novel educational programs to train new scientific personnel able to perform world-class research on advanced materials.

The most important obtained results, examples of their usage or application

The technical infrastructure of the laboratory with the total area of 200 sq.m has been established. The planned complete set of the lab equipment includes:

  • Materials Processing Equipment: Spark Plasma Sintering System model Labox- 625 and a unique system Labox-125VHD of spark plasma sintering with hybrid heating (Sinterland, Japan); system Impulse-BM for high-voltage consolidation of powder materials (Potok, Rostov, Russia); magnetic pulse powder pressing system Impulse 8-1 (Potok, Rostov, Russia); high-temperature vacuum tube and muffle furnaces (MTI, USA); a unique system of hot-pressing with an additional source of direct current (Oxy-Gon, USA); high-temperature vacuum microwave system Hamilab V6 (Synotherm, USA); isostatic press (AIP, USA); uniaxial presses (Carver, USA); ball mills, automatic mixers and dryers (MTI, USA); plasma sputtering unit (Denton, USA); dip coater (MTI, USA).
  • Auxiliary Equipment: molding press and glove box (MTI, USA); grinding and polishing machines (MTI, USA and Presi, France); cutting machines (MTI, USA and Presi, France); vibratory sieve shaker (Fritsch, Germany); and ultrasonicator (Qsonica, USA).
  • Materials Characterization Equipment: dilatometer (Netzsch, Germany); metallographic optical microscope (MTI, USA); digital scales (MTI and OHAUS, USA); automatic helium pycnometer (Micromeritics Instrument, USA); a universal mechanical testing machine (Galdabini, Italy); microhardness tester (Future-Tech, Italy); laser particle size analyzer (Fritsch, Germany); DSC-TGA thermoanalyzer (TA Instruments, USA).

 

The Laboratory team has made significant progress in a number of scientific fields. A number of the obtained theoretical and experimental results have been used in the development of new methods of consolidation of powder materials using electromagnetic fields.

The most important fundamental theoretical results include:

  • The first method of direct multi -scale modeling of sintering has been developed;
  • a conceptually new experimental approach of Multi-Step Pressure Dilatometry, which can be effectively used to determine the basic mechanisms of spark plasma sintering, has been elaborated;
  • new, having no previous analogues, models of inter-particle heat balance in the processes of spark plasma sintering and high-voltage electric discharge compaction have been put forward;
  • new and original ideas of the influence of the geometry of the inter-particle contacts on the spark plasma sintering efficiency have been proposed;
  • the first fully coupled finite element model of the process of hot pressing, activated by Joule heating, has been developed;
  • the world's first models of mass-transfer associated with densification and contact growth during microwave sintering under the influence of ponderomotive forces have been developed;
  • an original description of the physics of densification in the process of magnetic pulse compaction has been introduced.

The most important applied results include:

  • Preliminary experiments of the first ever carried out flash spark plasma sintering of silicon carbide powder (a material with a variety of application areas, including components of the high-temperature gas turbines, diesel filter systems, wear-resistant tools, fuel cladding, etc.) have rendered positive results;
  • experiments on the consolidation by spark plasma sintering and by high-voltage electric discharge compaction of iron -titanium composite powders, vanadium carbide, tantalum, zirconium nitride, oxide dispersion-strengthened (ODS) ferrite - martensitic steel powders with unique radiation-protective properties have been successfully carried out;
  • laboratory affiliates have carried out theoretical and experimental analyses of the processing of various types of structured powder materials, including sintering of layered ceramic composites for fuel cells and heavy alloys produced by liquid phase sintering.

The conducted research resulted in 63 publications, including 43 articles published, accepted for publication or submitted to refereed journals; two patents, two positive solutions for patents, and two filed patent applications; and 82 presentations at 26 conferences.

The commercialization potential and practical implementation of the already obtained results:

Laboratory associates are currently conducting research in the framework of the Program "Breakthrough", sponsored by the All-Russia Scientific Research Institute of Inorganic Materials on the two topics to create with the help of electromagnetic methods of consolidation novel types of reactor steels, as well as fundamentally new types of reactor fuel, which can dramatically improve the efficiency and environmental friendliness of the nuclear reactors:

  • «Modern methods of fabrication of nano-structural materials and techniques of fine structure research applied to ferritic-martensitic steels utilized in claddings» and
  • «Development technology, non-destructive techniques and remote control of pellets and fuel rods during re-fabrication of the mixed nitride fuel».

Qualifications of the research team, educational activities, the degree of involvement of young researchers and their role in the laboratory projects, the scientific achievements of young professionals

During the reported period 17 researchers with D.Sc. degree, 24 PhDs, 9 PhD and Master graduate students, and 8 undergraduate students participated in the scientific activities conducted in the Laboratory. Presently, the laboratory team includes more than 60% of employees under 35 years of age. Young researchers are co-authors of:  

  • 41 scientific articles (graduate students - 30 and undergraduate students - 20 scientific articles), published or accepted for publication in refereed journals;
  • 41 presentations at international scientific symposia.

Educational activities conducted at the Laboratory include:  

Students, graduate students and young researchers are co-authors of:  

 

Collaborations with external organizations:

Laboratory staff has established scientific interaction with domestic and international organizations: Baykov Institute of Metallurgy and Materials Science of the Russian Academy of Sciences, Moscow, Russia; All-Russia Scientific Research Institute of Inorganic Materials, Moscow, Russia; the Federal State Unitary Enterprise "Istok" , Fryazino, Russia; company «Diflex», Nizhny Novgorod, Russia; Institute of Electrophysics, Ural Branch of the Russian Academy of Sciences, Ekaterinburg, Russia; Don State Technical University, Rostov, Russia; Tomsk Polytechnic University, Tomsk, Russia; National Research University Nizhny Novgorod, Russia; Institute of Applied Physics of the Russian Academy of Sciences, Nizhny Novgorod, Russia; Frantsevich Institute for Problems of Materials Science of the National Academy of Sciences of Ukraine; Institute of Pulse Processes and Technologies of the National Academy of Sciences of Ukraine; Institute of Powder Metallurgy of the National Academy of Sciences of Belarus; California State University, San Diego, USA; Danish Technical University, Roskilde, Denmark; Royal Institute of Technology, Stockholm, Sweden; University of Leicester, city of Leicester, England; corporation Sinterland, Nagaoka, Japan; and other organizations.

Laboratory has been visited by 28 invited scientists from Russia, Ukraine, Belarus, USA, Japan, and Venezuela. All of the guest scientists presented lectures.

Conducted Research

The potential of traditional thermo-mechanical methods of materials treatment is substantially limited due to the mostly insufficient control of the evolution of the created material structures during processing. More accurate control capabilities for the processes of powder (in particular, nano-powder) synthesis and consolidation may be achieved by the application of electro-magnetic fields utilized by most modern field-assisted technologies, which include:

Spark-Plasma Sintering:
Spark-plasma sintering (SPS) is an emerging powder consolidating technique, which provides significant advantages to the processing of hard-to-deform materials into configurations previously unattainable. SPS consists essentially of conjoint application of high temperature, high axial pressure and field assisted sintering. The field component is associated with electric current passing through a powder specimen, or if the powder is non-conductive, through the conductive tooling. The electric field generates Joule heat, which provides the conditions of hot compaction; the current also enhances densification and improves the final grain structure in quite a remarkable way. This approach significantly shortens processing and enhances the performance time- and quality-wise. In particular, it carries the potential of maintaining the nano and sub-micro structure in nano-powder-based materials after high temperature consolidation.

 

Microwave Sintering:
A technology that is having the potential for meeting the goals of “better, faster, cheaper, and greener” is microwave technology for the sintering of variety of materials. A microwave system typically consists of a generator to produce microwaves, a waveguide for their transport, a cavity to manipulate the microwave field for a specific purposes and a control system for tuning power and monitoring the temperature. A microwave field makes it possible to heat both small and large shapes rapidly, uniformly, and efficiently. This is important in case of crystalline products where undesired grain growth can be prevented by rapid heating and short sintering periods. All these possibilities have the potential of greatly improving mechanical properties and the overall performance of the materials with the added benefit of low energy usage and cost.

 

High-Voltage Electric Discharge Compaction:
High-voltage electric discharge compaction (HVEDC) subjects a powder material to the combined action of a powerful electric discharge (10-3 – 10-5 s) and of mechanical pressure. The material, processed under high-power pulse electric current, can heat up to very high temperatures up to the plasma state. At the same time, the applied mechanical pressure produces the desired density of the obtained products. The advantages of this technology include high energy savings (up to 10 times compared to traditional consolidation techniques), environmental friendliness, the retention of the original material structure (nano-scale, or amorphous, in particular), the possibility of processing without atmosphere control, the capability of localized material treatment, and unique final properties of the produced components. HVEDC is demonstrated by video clip.

 

Magnetic Pulse Compaction:
The technology of Magnetic Pulse Compaction (MPC) has shown more promising results compared to other consolidation methods in compaction of nanopowders and long-length parts. For ductile materials, MPC allows obtaining nearly fully dense compacts without a heating stage. Powders of materials that lack ductility can be compacted by MPC to densities exceeding 0.8 of the theoretical density while full densification can be achieved by the subsequent sintering. Due to a strained state of the material and high concentrations of defects in the particles, the required sintering temperatures are reduced such that a nanostructure of the material can be preserved in the sintered state. The pulse duration in MPC ranges usually from tens to hundreds of µs.
 
 

Recent Publications 

 Initial stage of Free Pressureless Spark-Plasma Sintering of vanadium carbide: Determination of surface diffusion parameters

Inter-particle neck growth kinetics of vanadium carbide powder during initial stages of conventional and spark-plasma sintering has been investigated. Vanadium carbide (V8C7) micron-size powder has been subjected to both Free Pressureless Spark Plasma Sintering (FPSPS) ... 

 Localized Overheating Phenomena and Optimization of Spark-Plasma Sintering Tooling Design

The present paper shows the application of a three-dimensional coupled electrical, thermal, mechanical finite element macro-scale modeling framework of Spark Plasma Sintering (SPS) to an actual problem of SPS tooling overheating, encountered during SPS experimentation. The overheating phenomenon is analyzed...

 Outside Mainstream Electronic Databases: Review of Studies Conducted in the USSR and Post-Soviet Countries on Electric Current-Assisted Consolidation of Powder Materials

This paper reviews research articles published in the former USSR and post-soviet countries on the consolidation of powder materials using electric current that passes through the powder sample and/or a conductive die-punch set-up...

 Modeling and optimization of uniaxial magnetic pulse compaction of nano-powders

An experimental and theoretical study of the process of the uniaxial magnetic pulse compaction of nanopowders is conducted. The experimentation is carried out using aluminum oxide powders. The developed theoretical model includes the integrated description of the pulse magnetic field and of the dynamics of the mechanical system...

 Microwave Sintering: Fundamentals and Modeling

This paper reviews the basic physical notions underlying microwave sintering and the theoretical and numerical models of the microwave sintering process. The propagation and absorption of electromagnetic waves in materials, and the distribution of electromagnetic field in cavity resonators that serve as applicators for microwave processing are discussed and the...

 Spark-plasma sintering efficiency control by inter-particle contact area growth: A viewpoint

An ambiguity in the available experimental data on the presumably faster spark-plasma sintering (SPS) densification kinetics compared with conventional hot pressing of powders is pointed out. A hypothesis of the major impact of the evolution of the inter-particle contact area on the densification rate is put forward. It is argued that...

 Ponderomotive effects during contact formation in microwave sintering

An assessment of the ponderomotive effect contributions to the kinetics of single contact growth during sintering is carried out. A considerable free surface electromigration during microwave sintering in a polarized electromagnetic field is determined at inter-particle interfaces. It is shown that the electromigration flux reaches its maximum near the...

 Sintering of Multilayered Porous Structures: Part I-Constitutive Models

Theoretical analyses of shrinkage and distortion kinetics during sintering of bilayered porous structures are carried out. The developed modeling framework is based on the continuum theory of sintering; it enables the direct assessment of the cofiring process outcomes and of the impact of process controlling parameters. The derived “master sintering curve”-type...

 Sintering of Multilayered Porous Structures: Part II–Experiments and Model Applications

Experimental analyses of shrinkage and distortion kinetics during sintering of bilayered porous and dense gadolinium-doped ceria Ce0.9 Gd0.1 O1.95-d structures are carried out, and compared with the theoretical models developed in Part I of this work. A novel approach is developed for the determination of the shear viscosities ratio of the layer fully dense materials...

 Direct Multi-Scale Modeling of Sintering 

A new multi-scale numerical approach for the modeling of sintering of macroscopically inhomogeneous materials is put forward. The new approach does not require the formulation of material constitutive equations: it specifies material properties through the definition of macroscopic unit cells. As a result, the influence of any number of material structure parameters on sintering kinetics and on specimen distortion can be...

 The microwave effect on ceramic sintering

The evolution of pore structure during microwave sintering of ceramics is investigated based on a model of the non-thermal ponderomotive action of a microwave field in ionic crystalline solids. By means of numerical simulation it is demonstrated that the microwave field facilitates the collapse of faceted pores in the ceramics.

 Densification mechanisms of spark plasma sintering: multi-step pressure dilatometry

The effects of electrical current and mechanical pressure on the densification of spherical copper powder during spark plasma sintering (SPS) are examined. A novel multi-step pressure dilatometry method is introduced to compare the constitutive behavior of the copper powder...

      

Лаборатория работает при поддержке:

2012 © Национальный исследовательский ядерный университет «МИФИ»
115409, г. Москва, Каширское ш., 31