1. PROPERTIES OF MATERIALS Mechanical Properties Physical Properties

2. Properties Physical Mechanical Chemical Density Thermal Conductivity Electrical Conductivity Material response to applied load Corrosion

3. Glass or Amorphous Materials Crystalline Amorphous

4. Ceramic glasses Metallic glasses

5. Material property should be compatible with: Service conditions to which the component will be subjected to. Manufacturing process

6. Mechanical Property : Loading Tensile Compressive Shear

7. Mechanical Property : Tensile Test V

8. Load cells Extensometer

9. Definition of Parameters Engineering stress: Engineering strain: e L L o o L = Original area S = F/A0

10. Engineering stress strain curve

11. Engineering stress strain curve UTS

12. Engineering stress strain curve

13. Definiciones Yield strength (Y) Stress at which plastic deformation starts to occur Youngs modulus (E) S = Ee The slope of the linear elastic part of the curve Ultimate tensile strength (UTS) UTS Max Load Maximum engineering stress Stress at which necking or strain localization occurs 2% Offset yield strength Y(0.002) A O = Parameters

14. Tension test sequence

15. Tension test sequence Figure 2.2 ((b) Note: Outline In a) this Original figure, and final shape of a standard tensile-test specimen. of a tensile-test length sequence is showing denoted by stages in the lower case l. elongation of the specimen.

16. Necking

17. Ductility Ductility: Measure of the amount of plastic deformation a material can take before it fractures. % Elongation to Fracture: L L % El f O x 100 L O = % El is affected by specimen gage length. Short specimens show larger % El % Reduction in Area A A A x % O F 100 r A O = No specimen size effect when area in necked region is used

18. Typical mechanical properties at RT

19. METALS (WROUGHT) E (GPa) Y (MPa) UTS (MPa) (ELOGATION POISSOS (%) in 50 mm RATIO (v) Aluminum and its alloys 69-79 35-550 90-600 45-5 0.31-0.34 Copper and its alloys 105-150 76-1100 140-1310 65-3 0.33-0.35 Lead and its alloys 14 14 20-55 50-9 0.43 Magnesium and its alloys 41-45 130-305 240-380 21-5 0.29-0.35 Molybdenum and its alloys 330-360 80-2070 90-2340 40-30 0.32 Nickel and its alloys 180-214 105-1200 345-1450 60-5 0.31 Steels 190-200 205-1725 415-1750 65-2 0.28-0.33 Stainless Steels 190-200 240-480 480-760 60-20 0.28-0.30 Titanium and its alloys 80-130 344-1380 415-1450 25-7 0.31-0.34 Tungsten and its alloys 350-400 550-690 620-760 0 0.27 NONMETALLIC MATERIALS Ceramics 70-100 - 140-26000 0 0.2 Diamond 820-1050 - - - - Glass and porcelain 70-80 - 140 0 0.24 Rubbers 0.01-0.1 - - - 0.5 Thermoplastics 1.4-3.4 - 7-80 1000-5 0.32-0.40 Thermoplastics, reinforced 2-50 - 20-120 10-1 - Thermosets 3.5-17 - 35-170 0 0.34 Boron fiber 380 - 3500 0 - Carbon fibers 275-415 - 2000-5300 1-2 - Glass fibers (S, E) 73-85 - 3500-4600 5 - Kevlar fibers (29, 49, 129) 70-113 - 3000-3400 3-4 - Spectra fibers (900, 1000) 73-100 - 2400-2800 3 -

20. True Stress and True Strain t = F True stress: A d = dL True strain: Instantaneous area L L= ln( L = dL L L0 L0 ) M. P. Groover, Fundamentals of Modern Manufacturing 3/e John Wiley, 2007

21. True Stress (t) & Strain () More Accurate Measurement True Stress = Force = True Strain P 0 A l 0 l A P x y P A Ins eous Area tan tan l 0 = = ln ln ln 2ln = = D D D D A A l 2 0 0 0 t

22. Engineering Stress (S) /Strain (e) vs. True Stress () /Strain () True Stress & Engineering Stress (Up to necking) Conservation of volume: Al = A0l0 t = P A = P (A0l0 l ) = P Ao . l l0 = e ( l0 + l l0 ) = e (1+ e) True Strain & Engineering Strain (Up to necking) = ln( l l0 ) = ln( l0 + l l0 ) = ln(1+ e)

23. True Stress (t) & Strain ()

24. Comparision between True stress-Strain and Engg.Stress strain curve (UTS) t e = eE

25. True Stress (t) & Strain () Flow Curve: t = K n K = Strength co-eff n = Strain-hardening exponent

26. True Stress-Strain Curve Constitutive Eq. (plastic range) K :strength coefficient = K n (true stress at unit true strain) n :strain hardening exponent ( coeficiente de endurecimiento por deformacin) log = log K + n log

27. Typical values of K and n ( = Kn) MATERIAL K (MPa) n Aluminum, 1100-O 2024-T4 5052-O 6061-O 6061-T6 7075-O Brass, 70-30, annealed 85-15, cold-rolled Bronze (phosphor), annealed Cobalt-base alloy, heat treated Copper, annealed Molybdenum, annealed Steel, low-carbon, annealed 1045 hot-rolled 1112 annealed 1112 cold-rolled 4135 annealed 4135 cold-rolled 4340 annealed 17-4 P-H annealed 52100 annealed 304 stainless, annealed 410 stainless, annealed 180 690 210 205 410 400 895 580 720 2070 315 725 530 965 760 760 1015 1100 640 1200 1450 1275 960 0.20 0.16 0.13 0.20 0.05 0.17 0.49 0.34 0.46 0.50 0.54 0.13 0.26 0.14 0.19 0.08 0.17 0.14 0.15 0.05 0.07 0.45 0.10 Note: 100 MPa = 14,500 psi.

28. Different Flow Curves t t t Ideal Plastic material Ideal Elastic-Plastic material Piecewise linear

29. Resilience and Toughness Resilience: Ability of a material to absorb energy when deformed elastically and to return it when unloaded. Modulus of resilience= strain energy /volume 1 2 U e YS E R YS 0 2 2 = =

30. Resilience and Toughness Toughness: The ability of a material to absorb energy in the plastic range Ability to withstand occasional stresses above the yield stress without fracturing is Particularly desirable in many components

31. Resilience and Toughness

32. Modulus of resilience for various materials Modulus of Material E (GPa) YS(MPa) Resilience, (KPa) Medium-carbon steel 207 310 232 High-carbon spring steel 207 965 2250 Duralumin 72 124 107 Copper 110 28 3.5 Rubber 0.0010 2.1 2140 Acrylic polymer 3.4 14 28 Metallic Glass 150 -250 3000-5000 30,000

33. Fracture Brittle Ductile

34. Fracture

35. Effect of temperature

36. Effect of temperature

37. Effect of temperature

38. Effect of temperature