Modern Engineering materials for engineers.ppt

education

1. Unit –V
Modern Engineering Materials

2. Categories
MetallicGlasses
Shapememoryalloys
Nanomaterials
Biomaterials

3. Properties of Modern materials
Large optical nonlinearities
Optoelectronic property
High sensitivity to light
Large thermal and electrical conductivities
Good mechanical strength
Toughness
Ductility
lightness

4. Applications of Modern materials
Electronics
Photonics
Photoelasticity
Fibreoptics
Laser technology
Supersonic airplanes
Magnetic alloys for computer discs
Special ceramic for the heat shield of space shuttle

5. Properties of Metals
Crystalline in nature
ductile (strong in nature)
Non Transparent
Good conductors
Malleable

6. Properties of Glasses
Amorphous in nature
Brittle (weak)
Transparent
Bad conductors
Non-Malleable

7. Properties of Metallic glasses
Properties
of Metals
Properties
of Glass
Properties
of metallic
glass

8. Definition
Metallicglassesarenewtypeofmaterials
whichpossessboththepropertiesofmetalsand
glasses.

9. Properties of Metallic glasses
They have high strength
Good magnetic properties
High corrosion resistance
It will have both the properties of metals and
glasses

10. Glass transition temperature

11. Preparation of Metallic glasses
Melt spinning system (Quenching)
Twin roller system
Melt extraction system
Sputtering

12. Melt Spinning technique
(Quenching)

13. Types of Metallic glasses
Metal-metalloid glasses
Metals (Fe, Co, Ni) –Metalloid (Ge, Si, B, C)
Metal-metal glasses
Metal (Ni, Mg, Cu) –Metal (Nb, Zn, Zr)

14. Properties of Metallic glasses
Structural properties
Theydonothaveanycrystaldefectsand
dislocation
Metallicglasseshavetetrahedralclose
packingstructure

15. Properties of Metallic glasses
Mechanical properties
Theyhavehighstrength
Theyhavehighelasticity
Highlyductile

16. Properties of Metallic glasses
Electrical properties
Electricalresistivityishigh
Eddycurrentlossisverysmall
Thetemperaturecoefficientiszero

17. Properties of Metallic glasses
Magnetic properties
Ithasbothsoftandhardmagneticproperties
Theyexhibithighsaturationmagnetization
Theyhavelesscorelosses
Itexhibitsnarrowhysteresisloop

18. Properties of Metallic glasses
Chemical properties
Highlyresistanttocorrosion
Highlyreactiveandstable
Theycanactasacatalyst.Theamorphous
stateismoreactivethanthecrystallinestate
fromthecatalyticpointofview

19. Applications of Metallic glasses
Core transformers
Pressure vessels
very strong springs
tape recorders
computer memories
nuclear reactors
Surgical clips
Marine cables

20. In transformers

21. In Nuclear reactors

22. In springs

23. In computer memories

24. In marine cables

25. Modern materials
(Shape memory alloys)

26. Shape memory alloys
Shape–structure
Memory–recollectthepast
Alloys–collectionoftwoormore
elements

27. Shape memory alloys
Definition
Shapememoryalloysarethealloyswhich
changesitsshapefromoriginalshapetonew
shapewhileheatingorcoolingagainthematerial
willreturnbacktoitsoriginalshape.

29. Transformation temperature
Definition
Transformationtemperatureisthe
temperatureatwhichshapememoryalloys
changesfromnewshapetoitsoriginalshape.

30. Structures of SMA
SMA
Martensite
Twinned
martensite
Deformed
martensite
Austenite

31. S.noMartensite Austenite
I Martensiteis softby
nature
Austenite is hardby
nature
II It can be easily
deformable from one
shape toanother
shape
It is not so easy to
deform
IIIMartensiteexist only
at low temperature
Austenite exist onlyat
high temperature
IV It belongsto
monoclinic in
structure
It belongs tocubic in
structure

32. Structures of SMA

33. Processing of SMA

34. Macroscopic view of SMA

35. Microscopic view of SMA

36. Characteristics of SMA -pseudoelasticity

37. Characteristics of SMA -Hysteresis

38. Types of SMA
SMA
One way SMA
Two way SMA

39. Properties of SMA
Ithashighshapememorystrain
Thedensityishigh
Itismoreflexible
Ithashighmeltingpoint
Ithashighthermalstability
Ithashighcorrosionresistance

40. SMA in Eye glass frames

41. SMA in toys

42. SMA in helicopter blades

43. SMA in blood clot filter

44. SMA in coffee maker

45. SMA in teeth

46. Advantages of SMA
Very compact in nature
It is safe and smart
They are more flexible
They are non-corrosive

47. Disadvantages of SMA
Cost is high
Efficiency is low
Transformation occurs over range of
temperature

48. Biomaterials
Anymaterialswhichareincontactwithtissues,
cellsandfluidsoflivingbodyisknownas
biomaterials.

49. Classification of Biomaterials
Metalsandalloysofbiomaterials
Polymersbiomaterials
Ceramicsbiomaterials
Biopolymers

50. Application of Biomaterials
Metalsandalloysofbiomaterials
i)stainlesssteel–tomakebonescrews
ii)Ti-Al-Valloy–usedinimplantdevices
iii)Co-Cr-Mo–tomakestem

51. Application of Biomaterials
Polymerbiomaterials
i)Polyethylene–jointreplacement
ii)methylmethacrylate–bonecements
iii)Porouspolysulfone–orthopaedicimplants
iv)highdensitypolyethylene–dentalimplants

52. Application of Biomaterials
Biopolymers
i)Proteins
ii)polysaccrides
iii)nucleicacids
During the
growth of all
living
organisms

53. Bone screws

54. Bone cements

55. Dental implants

56. PMMA
Transparentthermoplastic,oftenusedasalight
weightshatterresistantalternativetoglass.
Syntheticpolymer

57. Properties of PMMA
Itisstrongandlightweightmaterial
Densityis1.17to1.20g/cm
Goodimpactstrengthhigherthanbothglassandpolystyrene
Transmitsupto92%ofvisiblelight
Filtersultravioletlightatwavelengthsbelow300nm.
Poorresistance
Ithasmaximumwaterabsorptionratioof0.3to0.4%

58. Uses -PMMA
Lensesforglasses
Instrumentclustersforvehicles
Shatterresistantpanelsforbuildingwindows,skylights,bulletproof
securitybarriers,furnitureandmanyotherapplications
Coatingpolymers

59. Medical applications -PMMA
Inorthopedicsurgery,PMMAbonecementisusedtoaffiximplants
andtoremodellostbone.
DenturesareoftenmadeofPMMA,canbecolormatchedtothe
patient’steethandgumtissue.
Incosmeticsurgery,tinyPMMAmicrospheressuspendedinsome
biologicalfluidareinjectedtoreducewrinklesorscarspermanently

60. Technical applications -PMMA
PMMAisusedinlaseddiscopticalmedia
ItisusedaslightguideforthebacklightsinTFT-LCDs
Plasticopticalfiberusedforshortdistancecommunication
Usedasmatrixinlaserdye
Usedtostopbetaradiationemittedfromradioisotopes
PMMAareusedasdosimeterdevicesduringthegammaradiationprocess.
PMMAusedasahybridrocketfuel.

62. Hydroxyapatite
(Ca
5(PO
4)
3OH) or
Ca
10(PO
4)
6(OH)
2
OHcanbereplacedbyfluoride,chloride
producingfluorapatiteorchrolorapatite.
Hexagonalcrystalsystem

63. Medical applications -hydroxyapatite
Canbefoundinteethandboneswithinthehumanbody.
Coreskeletoncanbetransformedintohydroxyapatitebyhigh
temperatures
Itburnsawayanyorganicmoleculessuchproteins,preventingan
immuneresponseandrejection
Usedforlocaldrugdeliveryinbone
Hipreplacements,dentalimplantsandboneconductionimplants

64. Ceramic materials -
compounds of metallic and non-metallic elements
Traditional ceramics –clay products (bricks, tiles, porcelain)
china ceramics –firing clay products

65. Introduction -Ceramics
Advancedceramicsaredevelopedforuseastools,rockets,missile
applications
Theseceramicspossesshighyoung’smodulus,highstrength,high
fracturetoughness
Furnaces,ovensasinsulators,crockeries,etc.,
Inartificiallimbsandteeth
Assuperconductingmaterials
Insonardevices,memorycoresoftransformer

66. Types -Ceramics
Naturalceramics–traditionalceramics
SiC,Al2O3,Si3N4andmanyvarietiesofoxides,carbides,nitrides,boridesand
morecomplexceramics
Functionalceramics
Abrasives–Alumina,Carborundum
Pureoxideceramics–MgO,Al2O3,SiO2,Zirconia
Fireclayproducts–bricks,tiles,porcelain
Inorganicglasses–windowglass,leadglass
Cementingmaterials–lime,portlandcements
Rocks–Granites,sandstones,etc
Minerals–calcite,quartz

67. Applications -Ceramics
Whitewares(olderceramics)
Tiles,sanitarywares,lowandhighvoltageinsulators,crucibles,jarandburners
Newerceramics
Borides,carbides,nitrides,singleoxides,silicates,metalloidandintermetallic
compounds
AdvancedCeramics
Internalcombustionengines,turbines
Electronicpackaging
Cuttingtools
Energyconversion

68. Advantages -Ceramics
Ceramicsarehard,stronganddense
Highresistancetothereactionofchemicalsandtotheweathering
Highcompressionstrength
Highfusionpoints
Excellentdielectricproperties
Goodthermalinsulators
Resistanttohightemperaturecreep
Cheaplyavailable