Ionel Chicina Department of Materials Science and Technology, - PowerPoint PPT Presentation

SOFT MAGNETIC NANOCRYSTALLINE/NANOSTRUCTURED SOFT MAGNETIC NANOCRYSTALLINE/NANOSTRUCTURED MATERIALS PRODUCED BY MATERIALS PRODUCED BY MECHANICAL ALLOYING ROUTES MECHANICAL ALLOYING ROUTES Ionel Chicina ş Department of Materials Science and Technology, Technical University of Cluj-Napoca, Romania European School of Magnetism, Cluj-Napoca, 9-18 Sept. 2007, 1

What are Nanocrystalline Materials ? schematic Polycrystalline materials Crystallite (grain) D = 0.1-10 2 µm Grain limits European School of Magnetism, Cluj-Napoca, 9-18 Sept. 2007, 2

What are Nanocrystalline Materials ? schematic Polycrystalline materials Crystallite (grain) D = 0.1-10 2 µm Grain limits European School of Magnetism, Cluj-Napoca, 9-18 Sept. 2007, 2

What are Nanocrystalline Materials ? schematic Polycrystalline materials Real images Crystallite (grain) D = 0.1-10 2 µm Grain limits European School of Magnetism, Cluj-Napoca, 9-18 Sept. 2007, 2

What are Nanocrystalline Materials ? schematic Polycrystalline materials Real images Crystallite (grain) D = 0.1-10 2 µm Grain limits Nanocrystalline materials Crystallite (grain) D = 1-100 nm Grain limits Atoms in grains Atoms in limits European School of Magnetism, Cluj-Napoca, 9-18 Sept. 2007, 2

What are Nanocrystalline Materials ? schematic Polycrystalline materials Real images Crystallite (grain) D = 0.1-10 2 µm Grain limits Nanocrystalline materials Crystallite (grain) Fraction of atoms in limits D = 1-100 nm 3 ∆ Grain limit thickness Grain limits = F Atoms in grains D Atoms in limits Crystallite size European School of Magnetism, Cluj-Napoca, 9-18 Sept. 2007, 2

What are Nanocrystalline Materials ? schematic Polycrystalline materials Real images Crystallite (grain) D = 0.1-10 2 µm Grain limits Nanocrystalline materials Crystallite (grain) Fraction of atoms in limits D = 1-100 nm 3 ∆ Grain limit thickness Grain limits = F Atoms in grains D Atoms in limits Crystallite size Examples: D = 5 nm F = 50% D = 10 nm F = 30% D = 100 nm F = 3% European School of Magnetism, Cluj-Napoca, 9-18 Sept. 2007, 2

Why are important Nanocrystalline Materials ? What really means the Nanocrystalline Materials ? When a Material is really Nano? European School of Magnetism, Cluj-Napoca, 9-18 Sept. 2007, 3

What are important Nanocrystalline Materials ? What really means the Nanocrystalline Materials ? When a Material is Nano? For example: Coercive field H C depend on intrinsic properties (anisotropy) structure (grain size, stresses, inclusions,etc. European School of Magnetism, Cluj-Napoca, 9-18 Sept. 2007, 3

What are important Nanocrystalline Materials ? What really means the Nanocrystalline Materials ? When a Material is Nano? For example: Coercive field H C depend on intrinsic properties (anisotropy) structure (grain size, stresses, inclusions,etc. Polycrystalline materials H C ~ 1/D H C when D and European School of Magnetism, Cluj-Napoca, 9-18 Sept. 2007, 3

What are important Nanocrystalline Materials ? What really means the Nanocrystalline Materials ? When a Material is Nano? For example: Coercive field H C depend on intrinsic properties (anisotropy) structure (grain size, stresses, inclusions,etc. Polycrystalline materials H C ~ 1/D H C when D and Nanocrystalline materials H C ~ D 6 H C when D and G. Herzer, Scripta Metall et Mater., 33 (1995) 1741-1756. European School of Magnetism, Cluj-Napoca, 9-18 Sept. 2007, 3

What are important Nanocrystalline Materials ? What really means the Nanocrystalline Materials ? When a Material is Nano? For example: Coercive field H C depend on intrinsic properties (anisotropy) structure (grain size, stresses, inclusions,etc. Polycrystalline materials H C ~ 1/D H C when D and Nanocrystalline materials H C ~ D 6 H C when D and A Material is Nanocrystalline when its Crystallite Size is lower then the Interaction Length of the considered Property! G. Herzer, Scripta Metall et Mater., 33 (1995) 1741-1756. European School of Magnetism, Cluj-Napoca, 9-18 Sept. 2007, 3

Nanocristalline/nanostructured (d < 100 nm) materials can be produced starting from: • vapours - inert gas condensation, sputtering, plasma processing, CVD • liquid - electrodeposition, rapid solidification • solid - mechanical alloying, mecanosynthese, severe plastic deformation, spark erosion European School of Magnetism, Cluj-Napoca, 9-18 Sept. 2007, 4

Nanocristallin/nanostructured (d < 100 nm) materials can be produced starting from: • vapours - inert gas condensation, sputtering, plasma processing, CVD • liquid - electrodeposition, rapid solidification • solid - mechanical alloying, mecanosynthese, severe plastic deformation, spark erosion Mechanical alloying Nanocristallins/nanostructured magnetic materials annealing modifies the structure and the microstructure European School of Magnetism, Cluj-Napoca, 9-18 Sept. 2007, 4

Mechanical routes for producing nanocrystalline powders What is mechanical alloying? European School of Magnetism, Cluj-Napoca, 9-18 Sept. 2007, 5

Mechanical routes for producing nanocrystalline powders What is mechanical alloying? Mechanical alloying (MA) Usually, we make alloys by involves the synthesis of melting together the components materials in solid state by high-energy ball milling European School of Magnetism, Cluj-Napoca, 9-18 Sept. 2007, 5

Mechanical routes for producing nanocrystalline powders What is mechanical alloying? Mechanical alloying (MA) Usually, we make alloys by involves the synthesis of melting together the components materials in solid state by high-energy ball milling Elemental Powders Mixture • Particles and grains are fractured Milling in high energy ball mill • Defects introduced in particles New phase • Temperature rise - diffusion European School of Magnetism, Cluj-Napoca, 9-18 Sept. 2007, 5

Mechanical routes for producing nanocrystalline powders What is mechanical alloying? Mechanical alloying (MA) Usually, we make alloys by involves the synthesis of melting together the components materials in solid state by high-energy ball milling Elemental Powders Mixture • Particles and grains are fractured Milling in high energy ball mill • Defects introduced in particles New phase • Temperature rise - diffusion European School of Magnetism, Cluj-Napoca, 9-18 Sept. 2007, 5

Mechanical routes for producing nanocrystalline powders What is mechanical alloying? Mechanical alloying (MA) Usually, we make alloys by involves the synthesis of melting together the components materials in solid state by high-energy ball milling Elemental Powders Mixture • Particles and grains are fractured Milling in high energy ball mill • Defects introduced in particles New phase • Temperature rise - diffusion D 1 C 1 D 2 D 1 C 2 B 1 B 1 C 3 B 2 European School of Magnetism, Cluj-Napoca, 9-18 Sept. 2007, 5

Mechanical routes for producing nanocristalline powders Mechanical alloying (MA) Mechanical milling (MM) refers to the involves the synthesis of process of milling pure metals or materials by high-energy ball compounds without solid state reaction milling - PROCESS Disc Ω » ω → shock mode process (SMP) Ω Vial ω Ω « ω → friction mode process (FMP) European School on Magnetism, Cluj-Napoca, 9-18 Sept. 2007, 6

Mechanical routes for producing nanocristalline powders Mechanical alloying (MA) Mechanical milling (MM) refers to the involves the synthesis of process of milling pure metals or materials by high-energy ball compounds without solid state reaction milling - PROCESS Disc Ω » ω → shock mode process (SMP) Ω Vial ω Ω « ω → friction mode process (FMP) European School on Magnetism, Cluj-Napoca, 9-18 Sept. 2007, 6

Mechanical routes for producing nanocristalline powders Mechanical alloying (MA) Mechanical milling (MM) refers to the involves the synthesis of process of milling pure metals or materials by high-energy ball compounds without solid state reaction milling - PROCESS Disc Ω » ω → shock mode process (SMP) Ω Vial ω Ω « ω → friction mode process (FMP) Dry milling Milling: Wet milling Cryomilling Three groups of parameters were identified, depending on: factors related to Factors depending Factors depending material or materials upon the milling upon processing mixture subjected to equipment, including milling. the milling bodies European School on Magnetism, Cluj-Napoca, 9-18 Sept. 2007, 6

Mechanical routes for producing nanocristalline powders Mechanical alloying (MA) Mechanical milling (MM) refers to the involves the synthesis of process of milling pure metals or materials by high-energy ball compounds without solid state reaction milling - Equipments Disc Ω » ω → shock mode process (SMP) Ω Vial ω Ω « ω → friction mode process (FMP) European School on Magnetism, Cluj-Napoca, 9-18 Sept. 2007, 6

Mechanical Alloying and Annealing Combining (MAAC) - What is this technique? Annealing the mixture milled MA Generally, synthesis of What's happening if we STOP the milling new material by MA process before the mechanical alloying needs a long time finishing and then we make an annealin g? V. Pop, O. Isnard and I. Chicinas, J. Alloys and Comp., 361 (2003), p.144-152. European School of Magnetism, Cluj-Napoca, 9-18 Sept. 2007, 7