Composites

1. Composites • Definitions and their aspects • Babbitt alloys • Classification of composites • Effect of reinforcing particles sizeon a hardness of composites • Effect of reinforcingparticle sizeon a strength of composites • Effect of reinforcing particles size on a wear behaviour of composites Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

2. Composites Author: Piotr Bobrowski 1.Definitions and their aspects Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

3. Definitions Composites: Materials made of at least two types of materials with different mechanical and chemical properties from the constituent phases. - the constituent materials work as matrix or reinforcement - resultant properties are not a simple sum of components properties L. Dobrzański „Podstawy nauki o materiałach i metaloznawstwo” Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

4. Matrix • continuous phase • joins the reinforcement together • transfers external loads onto the reinforcement • determines external shape • materials: • metals (MMC): Al, Mg, Ti, Fe, Ni, Co • ceramics (CMC): concrete, SiC, Al2O3, • polymers: polyesters, polyamides, epoxy resins, asphalt Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

5. Reinforcement • embedded into matrix • improvement of matrix properties: stiffness, hardness, fracture toughness,thermal shock resistance, wear resistance, friction coefficient, thermal conductivity • different forms: powder, fibers (continuous-discontinuous, aligned-random), laminates • materials: • metals: wires: Fe, powders: W, Mo • ceramics: fiberes: glass, SiC and carbon; particles: SiC and Al2O3, metal oxides • polymers: Kevlar, Nylon Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

6. Advantages • unique properties combining advantages of each constituent material • improved mechanical properties • possibility to tune materials properties • high wear resistance • excellent strength/weight ratio Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

7. Disadvantages • complex production methods • difficult processing (cutting, forming) • difficult joining • often impossible to repair • sometimes brittle • - high cost Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

8. Composites Author: Grażyna Kulesza 2. Babbitt alloys Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

9. Babbitt alloys • Babbitt, also called Babbitt metal or bearing metal, is any of several alloys used for the bearing surface in a plain bearing. • The original Babbitt metal was invented in 1839 by Isaac Babbitt in Taunton, Massachusetts, USA. Other formulations were later developed (and Isaac Babbitt's exact formulation is not known with certainty). To deemphasize the term's eponymous character, modern writers often lowercase it (babbitt metal—as with "diesel engine").It is preferred over the term "white metal", which also refers to bearing metal, because "white metal" is an ambiguous term with various meanings. Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

10. Using of babbittalloys • Low-speed equipment will use bronze bushings, preferably made of oilite bronze. Higher-speed equipment will use Babbitted bearings. • When a lubricant film cannot completely separate the moving parts of a bearing, friction and wear increase. The resulting frictional heat combined with high pressure promotes localized welding of the two rubbing surfaces. These welded contact points break apart with relative motion and metal is pulled from one or both surfaces decreasing the life of the bearing. This friction and welding is most common when like metals, such as steel or cast iron, are used as bearings – they easily weld together. Compatibility of bearing materials, therefore, and absorption of lubricant upon the bearing surface, is necessary to reduce metallic contact and extend bearing life • They easily adapt their shapes to conform to the bearing shaft and will hold a lubricant film. Foreign matter not carried away by the lubrication is embedded below the surface and rendered harmless. These characteristics are due to babbitt’s hard/soft composition Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

11. Using of babbittalloys • These are stationary sleeves for the rotating shaft which can be cast and machined precisely, and which are lubricated with oil. Because the stationary bearing is made of a very soft alloy, it won't scratch the crankshaft, and it will conform very well to the crankshaft. • Babbitt has good load carrying capacity between 800 PSI (5.5 MPa) and 1500 PSI (10.3 MPa) • Maximum operating temperature for Babbitt is 300º F (148.9 °C) . In motors 180º F (82.2 °C) to 190º F (87.8 °C) is considered running hot.  Some turbine applications run as high as 225° F (107.2 °C). Many technicians however, will set the alarm at 185º F (85.0 °C) and trip at 205º F (96.1 °C). • Melting temperature for common Babbitt varies from 350º F (176.7 °C) to 475º  F (246.1 °C) • Although Babbitted bearings can't take extremely high speeds, they can certainly take up to 4000 rpm if properly lubricated. • Special bonding techniques are required to metallurgically bond Babbitt to metal crankshaft Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

12. Tin Based Alloys - Chemical Composition (%) Chart Lead Based Alloys - Chemical Composition (%) Chart Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

13. Types of Babbittalloys Babbitt metal is used as the lining for bearing shells of cast iron, steel and bronze. Therearetwo basic types of babbitt: (1) high-tin alloys (2) high-lead alloys. Both are relatively low melting materials consisting of hard compound in a soft matrix. The compounds found in each group are similar; it is in the composition and properties of the matrix that they differ. • High-tin babbitt • used for high unit load and high operating temperature • excellent corrosion resistance, easy bonding, low friction resistance, low wearand less tendency for segregation and welding • excellent load-carrying characteristics, ispreferred for use under steady load conditions in steam and gas turbines, electric motors, blowers, and pumps. • higher quality • hardness up to 32BHN • good run-in properties and good emergency behavior in the absence of adequate lubrication. (2) Lead-based babbitt • verygoodfrictionalproperties, reasonablygoodcorrosionresistance • adequate for lower loads andmoderatetemperatures • antimonyand tinincrease thestrength, hardness of leadand improvescasting properties • theaddition of tin 10% tin,room-temperaturestrength and hardness reach a maximum • thoughalloys with lower tin content areeasier to handle in the kettle, but more difficult to bond • above18% of antimony alloybecomesexcessivelybrittle • is prone to separate into elemental lead and tin and has a lower thermal conductivity • much less expensive Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

14. Forming bearingsfromBabbittalloys Users of babbitt ingot melt the metal in iron kettles from which they can ladle or pump the molten alloy. The bearing shell or backing is pre-coated with tin for tin-base bearings or with lead/tin for lead-base bearings. While the coating is still molten, the white metal is cast onto the backing and allowed to solidify from the bond inward. This prevents contraction cavities at the bond and restricts the growth of intermetallic compounds at the interface between the bearing shell and the babbitt. The lining is then machined to a mirror-bright finish and specified thickness. Babbitt can also be sprayed onto the bearing shell with the use of a flame arc gun and babbitt wire. Babbitt Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

15. Composites Author: Honorata Kazimierczak 3. Classification of composites Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

16. Compositesare materials composed of a matrix material reinforced with any of a variety of fibersorparticles made from ceramics, metals, or polymers. Classification of composites Introduction: The reinforcingfibers/particles are the primary load carriers of the material, with the matrix component transferring the load fromfiber tofiber. Selection of the optimal reinforcement form and material is dependent on the property requirements of thefinished part. Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

17. Classification of composites I. Based on the shape of the reinforcement • fibre, • particulate • laminar Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

18. Classification of composites I. Based on the shape of the reinforcement • fibre, • particulate • laminar II. Based on the matrix material • polymer matrix • metal matrix • carbon matrix • ceramic and glasses matrix Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

19. Classification of composites I. Based on the shape of the reinforcement • Fibrous Composites: Fibers are pliable hair-like substances, built up by long chains of basics molecules. Fibers are very small in diametes in relation to their length. Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

20. Classification of composites I. Based on the shape of the reinforcement • 1) FibrousComposites: • Continuous/long fibresinmatrix: • unidirectional orientation of fibers. • bidirectional orientation of fibers (woven). • Discontinuous/shortfibresinmatrix: • unidirectionalorientation of fibres • random orientation of fibres Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

21. Classification of composites I. Based on the shape of the reinforcement 1) Fibrous Composites The most common fibers used in composites are : • Glass – most widely used fiber in polymer composites, the term fiberglass is applied to denote glass fiber-reinforced plastic (GFRP) • Carbon – are generally a combination of graphite. Graphite has a tensile strength three to five times stronger than steel and has a density that is one-fourth that of steel. • Boron – very high elastic modulus, but its high cost limits its application to aerospace components • Ceramics – Silicon carbide (SiC) and aluminum oxide (Al2O3) are the main fiber materials among ceramics. Both have high elastic moduli and can be used to strengthen low-density, low- modulus metals such as aluminum and magnesium • Metal – Steel filaments, used as reinforcing fiber in plastics Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

22. Classification of composites I. Based on the shape of the reinforcement 2) Particulate Composites: Particles • Are important materials form for metals and ceramics range in size from microscopic (less than 1 micron) to macroscopic (greater than 1 micron) • In the microscopic size range and proportion of imbedded material of 15% or less, the particles result in strengthening the matrix • In the macroscopic size range and proportion of imbedded material of 25% or more, the particles serve to share the load with the matrix material. Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

23. Classification of composites I. Based on the shape of the reinforcement • 2) ParticulateComposites: • Particulates (spheres, plates, ellipsoids, irregular, hollowor solid) inmatrix: • Alignedorientation of particles • Random orientation of particles • Dispersionstrengthened, as for the point above, but theparticle size<10−8m Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

24. Classification of composites I. Based on the shape of the reinforcement • 3) LaminanarComposites: • Laminates • Cladmetals • Sandwich structures Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

25. Classification of composites I. Based on the shape of the reinforcement • 3) LaminanarComposites: • Laminates • Largenumber of fibresin a thinlayeredmatrixisknown as lamina. • Various lamina containfibresineither one directionorindifferentdirectionsstackedin a specificsequence and cementedtogether. • Thisiscalled a laminate. Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

26. Classification of composites I. Based on the shape of the reinforcement • 3) LaminanarComposites: • Cladmetals • Are metal-metal laminarcomposites, containing a metal corewiththinouterlayers of another • metal. • Cladmetalsprovide a combination of goodcorrosionresistancewith high strength. Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

27. Classification of composites I. Based on the shape of the reinforcement • 3) LaminanarComposites: • Sandwich structures • Iscomposed of a thick, lowdensitycoreplacedbetweentwo high density face sheets. • Neitherthecore nor the face sheetisstrongorrigid, but thecompositepossessesboththeproperties. Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

28. Classification of composites I. Based on the matrix material • Polymer Matrix Compotises (PMC) • Are composed of a matrix from thermoset (Unsaturated Polyester (UP), Epoxiy(EP)) or thermoplastic (Polycarbonate(PC), Polyvinylochloride, Nylon, Polysterene) and embedded glass, carbon, steel. • Thermosetting resins are the most widely used polymers in PMC • Metal Matrix Compotises (MMC) • are composed of a metallic matrix (aluminum, magnesium, iron, cobalt, copper) and a dispersed ceramic (oxides, carbides) or metallic phase (lead, tungsten, molybdenum). Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

29. Classification of composites I. Based on the matrix material • Carbon Matrix Compotises (CAMC) • Consist of a carbon matrix reinforced with any combination of fibers or particles. • carbon/carbon composites (CCC) • (in which the reinforcement are discontinuous or continuous carbon fibers.) • Silison carbide fiber reinforcement composites • Ceramic and Glasses Matrix Compotises (CMC) • Ceramic Matrix Composites are composed of a ceramic matrix and embedded fibers of other ceramic material (dispersed phase). • Glass matrices have better dimensional stability than polymer or metal matrices , due to their low coefficient of thermal expansion. Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

30. Composites Author: Marta Gajewska 4.Effect of reinforcing particles sizeon a hardness of composites Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

31. Influence of reinforcing particles • type of particles (usually hard ceramicparticles) • particle size (generallythesmallerthebetter) • particle fraction (gen. thehigherthebetter) • particle shape • matrix-particleinteractions Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

32. Particle size decrease + + small particles better dispersion  composite homgenity small particles greaterinterfacial area between the strengthening phase and the matrix + small particle size precipitation hardening – like effect(retained at high temperatures)  finer grain sizein themicrostructure is produced higher hardness (HP relation) + small ceramic particles are less prone to fracture (lower porosity)  higher hardness – – increase in the specific surface higher interparticlefriction  decreased particle distribution decreasing the particle size  high number of reinforcing particlesagglomeration and clustering Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

33. Influence of particle size Generally in particulate reinforced composites: λ - distance apart fromthe reinforcements, f - fractional volume of the reinforcement, r - radius of the particles(assuming them to be spherical) J. Rahimiana, N. Ehsani, N. Parvinb, Journal of Materials Processing Technology 209 (2009) 5387–5393 R. Ekici, M. K. Apalak, M. Yıldırımb, F. Nair, Materials and Design 31 (2010) 2818–2833 Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

34. Reinforcement size vs hardness Al 1080/SiC The residual stress concentrates underneath the indenter for small particle size and spreads over a larger zone for large particle sizes R. Ekici, M. K. Apalak, M. Yıldırımb, F. Nair, Materials and Design 31 (2010) 2818–2833 Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

35. Reinforcement size vs hardness Al /Al2O3 • Higher hardness was observed in samples containing fineralumina particles: • greaterinterfacial area between the strengthening phase and the matrix • large alumina particles aremore prone to fracture (higher porosity) M. Rahimiana, N. Parvinb, Materials Science and Engineering A 527 (2010) 1031–1038 Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

36. Other approach Optimalisation of the relative particle size (RPS) ratio: RPS - ratio between the average size ofthe matrix particles and that of thereinforcementparticles RPS ratio optimalisation may lead to animprovement in the uniformity ofreinforcement distribution in MMCs and in turn improve the mechanicalproperties V.V.B. Prasad et al. / Materials Science and Engineering A337 (2006) 179/186 Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

37. Composites Author: Jagoda Poplewska 5. Effect of reinforcingparticle sizeon a strength of composites Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

38. Therearetwokinds of compositesstrengthened by particles: • strengthened with large particles of another phase >1μmand particlevolume >25 % (eg, polymer with fillerorconcrete) • impairedability to deformation of the matrix • dispersion-hardened materials - reinforcement particles have more orlessdiameters of 0,01÷0,1 μmand particlevolume 1 % ÷ 15 % (eg, metal alloys, where the metal is matrix and the reinforcement is any harder phase: thorium in nickel, Al/Al2O3, Cu/Al2O3) • inhibition of dislocationmotion Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

39. Impact of particle diameter component of strengthening the strengthening factor Strengthening factorKw: where: ReK – yeld strength of the composite Re0 – yeld strength of the matrix Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

40. Strengthening by particles • (metal/ceramic composites) Increase in tensile strength of aluminium materials by particle addition: Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

41. Strengthening by particles • (metal/ceramic composites) Increase in tensile strength of aluminium materials by particle addition: The strain hardening contribution Influence of induced dislocations Influence of the grain size Influence of the subgrain size Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

42. Strengthening by particles • (metal/ceramic composites) Increase in tensile strength of aluminium materials by particle addition: The strain hardening contribution Influence of induced dislocations Influence of the grain size Influence of the subgrain size Where: ∆σα – yeld strength contribution due to geometrical necessary dislocations and inner tension α – constant (values 0.5-1) G – shear modulus b – Burger’s vector ρ – dislocations density and: ∆T – temperature difference ∆C – difference in thermal expansion co- efficient between matrix and particle Фp – particle volume d – particle size Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

43. Strengthening by particles • (metal/ceramic composites) Increase in tensile strength of aluminium materials by particle addition: The strain hardening contribution Influence of induced dislocations Influence of the grain size Influence of the subgrain size Where: ∆σKG – yeld strength contribution from changes in grain size kY1 – constant D – resulting grain size and: Фp – particle volume d – particle size Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

44. Strengthening by particles • (metal/ceramic composites) Increase in tensile strength of aluminium materials by particle addition: The strain hardening contribution Influence of induced dislocations Influence of the grain size Influence of the subgrain size Where: ∆σSKG – yeld strength contribution due to changes in subgrain size kY2 – constant (typical value 0.05 MN m-3/2) DS – resulting subgrain size and: Фp – particle volume d – particle size Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

45. Strengthening by particles • (metal/ceramic composites) Increase in tensile strength of aluminium materials by particle addition: The strain hardening contribution Influence of induced dislocations Influence of the grain size Influence of the subgrain size Where: K – constant G – shear modulus b – Burger’s vector ε – elongation Фp – particle volume d – particle size Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

46. Example(Al/SiC) Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

47. Composites Author: Katarzyna Stan 6. Effect of reinforcing particles size on a wear behaviour of composites Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

48. For composite materials, the wear phenomena differ significantly from that of the monolithic material due to the multiple phase nature of the composite • The wear mechanism, isgoverned by various intrinsic factors such as: • hardness difference between counter faces, • hardness of the reinforcement and the matrix, • amount of reinforcement, • the size and shape ofreinforcement, • distribution of reinforcement, • bond strength between the reinforcementand the matrix, • interfacial reaction between the reinforcement and thematrix, • porosity and poredistribution. Varun Sethi: Effect of Aging on Abrasive Wear Resistance of Silicon Carbide, Particulate reinforced aluminum matrix composite, Master thesis, 2007 Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

49. A variety of mechanisms may be responsible for wear of composites. Wear controlled by the wear rate of the reinforcing phase: hardreinforcing phase reduction of the wear rate of the composite reinforcing phase could be pulled out of thecompositeand trapped at the interface composite may wear by abrasive wear mechanisms Different mechanism - the matrix reinforcing phase interface is weak, cracks may nucleate at the matrix/particle interface, either at the surface or below the surface. The surface cracks will be responsible for particle pull-out whereas the subsurface cracks may lead to delamination-type wear. In that case the wear rate of the overall composite depends, in a complicated way, on the particle size, interparticle spacing and the strength of the particle-matrix interface. As a result, the wear rate of a composite could be larger or smaller than the wear rates of the constituent phases Varun Sethi: Effect of Aging on Abrasive Wear Resistance of Silicon Carbide, Particulate reinforced aluminum matrix composite, Master thesis, 2007 Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim

50. Metal matrix composites (MMCs) Friction and wear behavior of metal matrix composites will depend on the nature of particle reinforcements and the matrix, and the interface between them. Hard particles with hardness 4-31Gpa, such as SiC, Al2O3, Silica, B4C and TiB2 Soft particles with hardness below 4GPa, such asgraphite and MoS2 which are primarily added for solid lubrication purposes Varun Sethi: Effect of Aging on Abrasive Wear Resistance of Silicon Carbide, Particulate reinforced aluminum matrix composite, Master thesis, 2007 Interdyscyplinarne studia doktoranckie z zakresu inżynierii materiałowej z wykładowym językiem angielskim