1. Material Properties

2. Material properties 1.Physical properties Quantities that characterize the behavior of a material in response to physical phenomena other than mechanical forces …(e.g. such as heat, electricity, radiation) 2. Chemical properties Quantities that characterize the behavior of a material in response to other chemicals in its environment 3. Mechanical properties Quantities that characterize the behavior of a material in response to external, or applied forces

3. Physical properties color –light wave length specific heat – the heat required to raise the temperature of one gram of a substance by one degree celsius (J/kg K)

4. Physical properties 3 density – mass per unit volume expressed in such units as kg/cm 3 thermal conductivity –rate at which heat flows through a given material (W/m K)

5. Physical properties melting point – a temperature at which a solid begins to liquify electrical conductivity – a measure of how strongly a material opposes the flow of electric current (Ω ⋅ m)

6. coefficient of thermal expansion – degree of expansion divided by the change in temperature (m/°C) Physical properties

7. Chemical properties corrosion resistance - a material's ability to resist deterioration caused by exposure to an environment Byproducts resulting from decay- if the material decays, what are the resulting chemicals

8. Mechanical properties Compressive stress (or compression) is the stress state caused by an applied load that acts to reduce the length of the material (compression member) in the axis of the applied load, in other words stress state caused by squeezing the material. Tensile stress is the stress state caused by an applied load that tends to elongate the material in the axis of the applied load, in other words the stress caused by pulling the material. Shear stress is the stress state caused by the combined energy of a pair of opposing forces acting along parallel lines of action through the material, in other words the stress caused by faces of the material sliding relative to one another. An example is cutting paper with scissors.

9. Deformation of the material is the change in geometry created when stress is applied Strain or reduced deformation is a mathematical term that expresses the trend of the deformation change among the material field. Strain is the deformation per unit length. Deflection is a term to describe the magnitude to which a structural element bends under a load. Mechanical properties

10. ductility – a measure of how much strain a material can take before rupturing malleability – the property of a material that can be worked or hammered or shaped without breaking brittleness –breaking or shattering of a material when subjected to stress (when force is applied to it) Mechanical properties

11. elasticity – the property of a material that returns to its original shape after stress (e.g. external forces) that made it deform or distort is removed plasticity - the deformation of a material undergoing non-reversible changes of shape in response to applied forces

12. Mechanical properties toughness – the ability of a material to absorb energy and plastically deform without fracturing hardness – the property of being rigid and resistant to pressure; not easily scratched machinability – the property of a material that can be shaped by hammering, pressing, rolling

13. Forming Processes: Forging - a manufacturing process where metal is shaped by plastic deformation under great pressure into high strength parts. Casting – pouring or injecting molten metal into a mold containing a cavity with the desired shape

14. MATERIALS` PROPERTIES ELASTICITY - the ability to flex and bend when forces are applied and then return to normal when the forces are removed (eg. an elastic band). MALLEABILITY - if a material can be deformed in all directions by such as hammering and pressing without it cracking or splitting it is said to be malleable. These materials need not be strong but they need to be 'plastic'. That is they need to be able to be bent often without breaking. Lead is a good example of a metal which is malleable. DUCTILITY - usually means the ability of a material to be stretched twisted or bent without breaking. All ductile materials are malleable but all malleable materials are not necessarily ductile. For example clay can be easily shaped but when you try to stretch it, it breaks. STABILITY Materials which are stable resist changes in size and shape, which can often be caused by weather, particularly wet or dry conditions. Wood tends to warp and twist if it gets too wet or dry. Plastic tends to bend and stay bent if it is subject to constant force. This stretching due to force is called 'creep'. It is most important that certain objects such as turbine blades resist 'creep' because they are subjected to a lot of rotational force and high temperatures which are known to cause 'creep'. HARDNESS Any material which can resist wear and tear, denting and twisting and bending is said to have the quality of hardness. Drills, files emery cloth and glasspaper have these qualities. TOUGHNESS The ability to withstand sudden shocks or blows without it fracturing. It can also be applied to the ability of a material to withstand cracking if it is subjected to bending forces or shear forces. BRITTLENESS This is the opposite of toughness. Materials that are brittle cannot withstand any strain before they crack or break. Two good examples of this type of material would be acrylic and glass.

15. What Materials to Choose From?

16. Material families / sub- families CeramicsMetalsPlasticsComposites Materials Elastomers Thermosets Thermoplastics Non-ferrous Ferrous Sub-family Family (Ashby)

17. Material sub-families / classes Metals Materials Ferrous Sub-family Family Classes Cast iron Carbon steel Alloy steel Stainless steel

18. Metals Non-ferrousFerrous Metals aluminum brass bronze copper lead magnesium nickel tin titanium tungsten zinc cast iron carbon steel alloy steel stainless steel

19. Elastomers Thermosets Thermoplastics Polymers butyl fluorocarbon neoprene nitrile polysulfide rubber silicone alkyd epoxy melamine phenolic polyester urethane ABS acetal acrylic nylon polycarbonate polyethylene polypropylene polystyrene vinyl Natural and synthetic rubbers Polymers

20. Cross-linking No chemical reaction

21. Ceramics alumina beryllia diamond magnesia silicon carbide silicon nitride zirconia

22. Composites carbon fiber ceramic matrix glass fiber Kevlar metal matrix Composites

23. Carbon fiber Style 282 bidirectional. Araldite epoxy resin with HY956 additive. Manufacturing process

24. Composites Ossur Flexwalk College Park Foot Otto Bock Advantage Pie protésico dinámico 2004 Pie protésico dinámico 2005

25. Composites Marlon Shirley Ossur Cheeta Flex-Foot Cameron Clapp Otto Bock C-Leg Date of birth: April 21, 1978 Hometown: Thatcher, Utah Current Home:San Diego, CA Date of birth: Sep 15, 1986

26. Property profiles by family

27. Materials selection prospective materials and processes screening rating rejected materials and processes best material(s) and processes functional? manufacturable? relative performance? feasible materials and processes

28. Screening: Materials first approach Application Information 1. Applied loads magnitude cyclic nature (steady, fatigue) rate (slow, impact) duration (creep) 2. Ambient conditions temperature moisture sunlight chemical liquids/vapors 3. Geometry of end product 4. Safety 5. Cost

29. Rating: Material indices Given the same cost/volume… which is stronger? index = Strength/cost Given the same cost/volume… which is stiffer? index = Young’s modulus/cost

30. Ashby Chart How can we use it?

31. Which properties do the following materials possess? MaterialProperties aluminium rubber ceramics steel copper lead nylon cast iron wood

32. Which properties do the following materials possess? MaterialProperties aluminiumlightness ; strength rubberelasticity ; insulation ceramicsthermal resistivity steelstrength copperconductivity ; corrosion resistance leadhigh density; ductility nylonstrength ; toughness cast irondamping capacity woodinsulation ; environmental friendliness

33. Find application for the following engineering materials: MaterialApplication aluminium rubber ceramics steel copper lead nylon cast iron wood

34. Find application for the following engineering materials: MaterialApplication aluminiumfoil; aircraft; window frame rubbertyres,; seal; gasket ceramicsfurnace; brick steelsection; pipe copperpipe; cables leadstorage battery; radiation protection ballast; bullets nylonrope; clothing cast ironengine block; valves woodfurniture; deck

35. Some of the strongest materials MaterialTensile StrengthUTS (Ultimate Tensile Strength) carbon nanotubes 62000 MPa (theoretical300000 MPa) 48000 kNm/kg carbon fibre 5650 MPa 3200 kNm/kg glass fibre 4700 MPa 1340 kNm/kg spider web 1000 MPa 900 kNm/kg high-strength steel 1200 MPa 154 kNm/kg

36. Some of the best conductors MaterialConductivity silver 63 x 10 6 S/m (1/ohm) copper 59.6 x 10 6 S/m (1/ohm) gold 45.2 x 10 6 S/m (1/ohm) aluminium 37.8 x 10 6 S/m (1/ohm)

37. Some of the best insulators MaterialSpecific resistance (PET) polyethylene terephthalate (PET) 10 20 ohm glass 10 14 ohm rubber 10 13 ohm

38. Materials with the greatest densities gold - 19300 kg/m 3 uranium - 19100 kg/m 3 lead - 11340 kg/m 3 steel - 7800 kg/m 3