1. 8.1 ME 340: Materials & Design CHAPTER 8 (ch. 3 in ref.1) ENGINEERING MATERIALS AND THEIR PROPERTIES

2. 8.2 ME 340: Materials & Design MATERIALS – are the food of design This chapter presents the full shopping menu or list Successful product= -good value for money. -Gives pleasure to user -Uses best material for job -Fully exploits their potential-brings out their flavor Don’t forget though that it is not materials we are after it is certain profile of properties that can be provided by any given material

3. 8.3 ME 340: Materials & Design CLASSES OF ENGINEERING MATERIALS

4. 8.4 ME 340: Materials & Design Each material can be thought of as having a set of attributes; it’s properties We consider property-profile And the material name is the identifier for a particular property profile

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6. 8.6 ME 340: Materials & Design The bulk modulus gives the change in volume of a solid substance as the pressure on it is changed, For isotropic elastic solids Data books list values for all 4 properties We will use eqn. 3.2 for E values

7. 8.7 ME 340: Materials & Design STRENGTH of a solid:Requires careful definition For METALS 0.2% offset yield strength POLYMERS Stress at which Stress-strain curves become Markedly non-linear: typically at strain of 1% CERAMICS Crushing strength Fracture strength

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9. 8.9 ME 340: Materials & Design When difficult to grip specimen (e.g. ceramics) Larger by ~1.3 than test in tension WHY???

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12. 8.12 ME 340: Materials & Design Hardness = load/projected area INCORRECT, What is correct eqn.??

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15. 8.15 ME 340: Materials & Design Cyclic loading  fatigue limit or fatigue life. Fatigue ratio f  dimensionless quantity (f /  y )

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17. 8.17 ME 340: Materials & Design Service temperature And softening temp Kinetic factor Units: s -1 Reference stress Thermal shock in K 1/3Tm or 2/3 Tg

18. 8.18 ME 340: Materials & Design K p =parabolic rate constant

19. 8.19 ME 340: Materials & Design WET CORROSION  More complicated and is measured on a a scale, rather than a rate equation.