Alla Byikovskaya

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Crystallization of metals - YouTube  See details »

 
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  • 00:03: [music] Science and Technology today impose the increasing requirements metal quality demand high wear resistance capacity resist shock loads
  • 00:30: [music] a long time withstand elastic cyclic voltage [music] keep long cutting properties when large tro all processing [music] need increased high elasticity
  • 01:00: corrosion durability [music] but even a cursory it is impossible to list all claims that apply to Metals and alloys our technicians up [music] the necessary properties metals acquired in a result of perform some process smelting operations, and
  • 01:32: and casting followed by crystallization the flower is subjected to rolling forging and stamping [music]
  • 02:00: [music] melt can be receive fittings casting transmitters the ins and outs of casting shape [music] To obtain metals specified properties must first all provide high quality the structure of the film [music]
  • 02:40: Many solids have crystal the structure for which characteristically regular arrangement of atoms crystal structure It is reflected not Only in the outer form many it is inherent in minerals also all metal
  • 03:07: metals crystallize body-centered and cubic lattice verge centered cubic lattice hexagonal compacted metals consist of a plurality of crystals irregularly shaped crystallite
  • 03:30: home adjacent to each other and having various crystals graphic same orientation as the crystals formed from liquid metal supercooled liquid metal comprises from randomly moving particles atoms or ions result chaotic movement atoms some volumes fluid may some point
  • 04:00: create a configuration they are located in the same as well as in a crystal forming a right grill if the size of these smaller entities critical [music] they are unstable and decay process this may repeat multiple particles
  • 04:31: of unsustainable provisions try to get to more resistant [music] because the spontaneously occurring processes occur in direction energy reduction system [music] bud and sizes greater than the critical power profitable so they
  • 05:01: become centers crystallization infection and further growth crystals there is also training centers [music] while in other parts of liquid there are centers new crystals [music]
  • 05:30: crystal size increases as long as it fills entire volume of metal [music] depending on the degrees hypothermia melt growth crystals can occur for a variety of mechanism sufficiently great
  • 06:00: supercooling melt atoms of the fluid joined directly to surface growing crystal [music] this causes roses normal [music] at lower hypothermia ah crystal growth done by joining surface and two-dimensional
  • 06:30: three-dimensional nuclei [music] they grow along the edge such an increase is called tangentially at the same time on the brink can grow
  • 07:00: several embryos [music] thermodynamic stimulus crystallization It is to reduce specific free energy critical size fetus can determined from analysis change free energy system
  • 07:32: [music] genetics crystallization metals It is defined by two options speed education nucleation centers crystallization and linear velocity crystal growth
  • 08:04: these settings crystallization depends on the hypothermia metal useful information about mechanism crystallization can get on transparent model objects [music]
  • 08:44: [music] micra modern keno technique allows see and capture nucleation and growth these amazing and
  • 09:00: diverse form ladders [music] [music] and the birth and growth of new previously formed crystals It continues until has not yet depleted liquid not
  • 09:30: [music] if in the process crystallization hypothermia or supersaturation fluids decrease formed crystals dissolves [music]
  • 10:01: shape and internal crystal structure determine the nature substances and conditions crystallization at low supercooling grow crystals hexagon shape period their growth rapidly growing you screen Krynica [music]
  • 10:36: [music] [music]
  • 11:04: Bailiffs can grow the form of fibers [music] [music]
  • 11:31: [music] often such growth crystals It takes place in one direction [music] with a large supercooling liquid birth dendritic or tree primary crystals reason dendritic crystallization not the same growth rate police officers in different directions
  • 12:02: [music] from the main stem from M3 to grow secondary branches and branches and more high-order [music] [music] these crystals remind fancy ice patterns
  • 12:34: [music] under special conditions some substances crystallizes form of her ride of [music] radially located branches spherulites grow from one center [music] a [music]
  • 13:03: at Crystals often have layered structure [music] for its crystals characterized by fairly strict
  • 13:30: rhythm [music] some cases may form and layers concentric shape [music] when the surface
  • 14:01: crystal leaves screw dislocation formed iran growth Reverend growth Crystal was like married in a liquid on the Shubnikov growth can imagine how accession atoms steps imaginary spiral staircase [music]
  • 14:32: adjusting the degree hypothermia can change the value grains large crystals formed at low degrees hypothermia and [music]
  • 15:14: at greater supercooling formed numerous fine crystals [music]
  • 15:34: consider formation ingot structure example crystallisation Vova [music]
  • 16:02: crystallization starts from the walls molds and develops in reverse direction heat dissipation [music] conventional structure popped matches structure the steel strip which is one hundred and structure years ago for the first time He described Chernov
  • 16:33: tiles consists of three main areas external fine-grained the so-called brown zone columnar crystals and the central zone is oral crystals the crystallization formed shrink sink and porosity [music] present We learned how to get
  • 17:00: Single crystals high degree of perfection and purity [music] most perfect crystals grown Czochralski method This method is based on extension crystal melt [music]
  • 17:55: another effective a method for producing Single Crystals zone melting
  • 18:02: [music] Single crystals It has unique properties and the future will find used in many branches of engineering Single crystals superalloys promising to blade production turbine jet engines [music] way to develop
  • 18:31: obtaining metals best structure most important and perspective direction research in metallurgy [music]