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Dr. Alagiriswamy A A , (M.Sc, PhD, PDF) Asst. Professor (Sr. Grade),

Dr. Alagiriswamy A A , (M.Sc, PhD, PDF) Asst. Professor (Sr. Grade), Dept. of Physics & Nanotechnology, SRM-University, Kattankulathur campus, Chennai. UNIT III. Lecture 2. Mar. 18/2014. Outline. Shape memory alloys (SMAs) Metallic glasses or amorphous metals

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Dr. Alagiriswamy A A , (M.Sc, PhD, PDF) Asst. Professor (Sr. Grade),

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  1. Dr. Alagiriswamy A A, (M.Sc, PhD, PDF) Asst. Professor (Sr. Grade), Dept. of Physics & Nanotechnology, SRM-University, Kattankulathur campus, Chennai UNIT III Lecture 2 Mar. 18/2014

  2. Outline • Shape memory alloys (SMAs) • Metallic glasses or amorphous metals • examples, features, preparation, applications • Composites • Features, examples, products • Advanced ceramics • Examples • Categories, preparation (processing techniques) • properties • features, examples

  3. Before I proceed Stents as SMAs Ability to bend, stay bent, and regain its shape Uses internal atomic arrangement to recognize their shapes Austentite (high temperature cubic phase) & Martensite (low temperature deformed or twinned phase)

  4. Metallic glass = Amorphous metal Metals (have long range order, ductility, malleability, lusture) Glasses (lack of long range order – short range order, no crystallinity features ) It's called metallic glass, and it shines like a mirror, but when you drop a piece of it to the floor, it doesn't break. In fact, it bounces--wildly--thanks to its unusual atomic structure can it be called as a liquid metal Conventional metals crystallize when cooled from a liquid to a solid. But metallic glass cools to an amorphous (glassy) structure, making it much stronger, lighter, and springier than other metals--and virtually corrosion-proof low hysteresis (may be a soft magnetic) Metallic Glass: A Revolution of Metallurgy

  5. X-ray spectrum of ……….. (a) crystalline material and (b) amorphous material

  6. Unique features of MG……….. (b) Magnetic properties (a) Mechanical properties

  7. Imagine a razor blade that stays super sharp for a year. A golf club so springy it can drive a ball farther than a titanium club. An artificial hip implant that is stronger and more flexible than current implants. A cell phone case that is almost indestructible More interesting features of MG ……

  8. Fabrication of MG …

  9. Non-metallic elements, need not be inorganic Hard and brittle, toughness, Chemically inert, having high melting points Electrically/thermally considered to be insulators Advanced Ceramic Materials also known as traditional ceramics Greek :- keramos - clay Sanskrit :- Cer - Cook/potter • Ceramic materials • Traditional ceramics (bricks, porcelain) • Advanced ceramics (SiC, Si3N4, Al2O3)

  10. A few applications of Adv. Cer…..

  11. Ceramics Metals Comparison metals v ceramics

  12. Material preparation Milling/sizing to form desired particle size Forming or casting Pressing into a die – to form a shaped product Thermal treatment Drying: to remove water from the plastic and the process is carried out in the range 200 to 3000C. Sintering: small particles of a material bonded together - solid-state diffusion. During this process ceramic porous product is made into a dense coherent product. Processing of advanced ceramics

  13. potential applications of Advanced Ceramics

  14. Natural composites: Wood (cellulose/lignin) Bone (apatite/collagen) Nacre ( Mother of pearl) (Aragonite/protein) Granite (quartz, feldspars…) Composites A composite is basically a material that contains both a reinforcing material to provide strength and stiffness and a matrix material to surround and hold the reinforcement together.

  15. features • Engineered materials • (reinforcing phase, matrix phase) • Orthotropic :- depends on the direction of the external load applied • Difficult to explain the mechanical properties • Shock/impact creates failure at micro/macro level • Fiber reinforced, glass reinforced, carbon reinforced composites

  16. What are the advantage of composites ? Light weight High strength & stiffness Reinforcement fibres can be arranged to follow the direction of principle loads and stresses Good fatigue resistance Very low coefficient of thermal expansion Good environmental and corrosion resistance The ability to manufacture complex shapes by moulding results in cost-effective production

  17. Applications as

  18. Applications as

  19. Thanks for the kind attention send us your queries/feedback to a.alagiriswamy@gmail.com alagiriswamy@ktr.srmuniv.ac.in

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