Advanced electric pulse consolidation methods of powder materials
Emerging technologies of field-assisted powder consolidation are studied and further advanced at the Key Laboratory for Electromagnetic Field Assisted Processing of Novel Materials at Moscow Engineering Physics University. 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).
The laboratory equipment includes: 1) Materials Processing Equipment: Spark Plasma Sintering System model Labox- 625 and a unique system Labox-125VHD of spark plasma sintering with hybrid heating (Japan); system Impulse-BM for high-voltage consolidation of powder materials; magnetic pulse powder pressing system Impulse 8-1 (Russia); high-temperature vacuum tube and muffle furnaces; a unique system of hot-pressing with an additional source of direct current; high-temperature vacuum microwave system Hamilab V6; isostatic press; uniaxial presses; ball mills, automatic mixers and dryers; plasma sputtering unit; dip coater (USA); etc, 2) Auxiliary Equipment: molding press and glove box; grinding and polishing machines; cutting machines (USA, France); vibratory sieve shaker (Germany); ultrasonicator (USA), 3) Materials Characterization Equipment: dilatometer (Germany); metallographic optical microscope; digital scales; automatic helium pycnometer (USA); a universal mechanical testing machine; microhardness tester (Italy); laser particle size analyzer (Germany); DSC-TGA thermoanalyzer (USA).
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; original description of the physics of densification in the process of magnetic pulse compaction has been introduced. New constitutive models of spark-plasma sintering taking into account thermal and non-thermal mechanisms of material transport are explored based on fundamental experimentation and computer simulations. Ultra-rapid field-assisted break-through consolidation technologies are developed for the processing of hard and super-hard materials. New technological routes of the fabrication of functionally structured powder components, including ODS steels and mono-nitride powders by spark-plasma sintering are established. Novel multi-scale thermo-mechanical model of high-voltage electric discharge consolidation of conductive powders is developed. New hybrid field-assisted sintering techniques are elaborated.