Term
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Definition
Hardened Steel or Tungsten ball
Brinell Hardness (HB) |
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Term
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Definition
Cone shaped diamond. 120° angle
Rockwell C hardness (HRC) |
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Term
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Definition
Ability of the material to absorb energy without breaking.
Determined by either Izod or Charpy pendulum. |
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Term
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Definition
Ability of the material to absorb energy without underoing permanent deformation.
Determined by either Izod or Charpy pendulum. |
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Term
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Definition
| Subjected to variable load, the material will fail at lower stress than a static test. |
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Term
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Definition
| Materials subjected continuously to static load exhibit a progressive increase in elongation. |
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Term
| What Temp will creep occur at for metals and plastics? |
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Definition
Metals - creep occurs at temp above 1/3*melting point
Plastic - creep could occur at room temp |
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Term
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Definition
| Subject to higher temp, materials expand. |
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Term
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Definition
| Property of the material to conduct heat, the higher the TC, the faster heat transfers across the material. |
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Term
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Definition
| Ability of materials to conduct electrical current. |
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Term
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Definition
| Alloys made of iron and carbon |
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Term
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Definition
| Ability to withstand stress without failure. |
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Term
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Definition
| Heats material above upper critical, then cools. Increases ductility, softness. Relieves internal stress |
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Term
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Definition
| Like annealing, but cools in less time. Less ductility. |
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Term
| Quenching and Tempering (through-hardening) |
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Definition
| Quenching is normally liquid cooled, increases strength, but makes brittle. Tempering increases ductility at the expense of strength. In order to be quenchable, the carbon must be more than .2% |
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Term
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Definition
Uneven material.
Very good casting properties |
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Term
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Definition
(carbon distributed in flakes)
Has good machinability, lubricity and damping properties.
Used for machine frames, engine blocks, gears. |
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Term
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Definition
Carbon distributed in small spheres - globular cast iron.
Used for gears, small crankshafts and camshafts. |
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Term
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Definition
| an alloyed heat treatable cast iron having higher tensile strength and better ductility. |
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Term
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Definition
| aluminum alloys are widely used, espeically when saving weight is important. The main alloying components are silicon and copper. It has good casting properties and also could be forged; good machinability. |
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Term
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Definition
copper alloyed with tin - bronze
copper alloyed with zinc - brass
Very good corrosion resistant. Bronzes are widely used in marine application.
Special bronzes: phosphor bronze, aluminum bronze. Berylium bronze, etc.
Brass is mainly used for lamps, musical instruments, and artillery shells. |
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Term
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Definition
Used for small cast parts very lightly loaded.
Also used as corrosion inhibitor for steel: galvanized steel |
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Term
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Definition
The lightest engineering metal.
Used where weight is extremely important: hand held toosl, aero and automotive industry. Most active material on the galvanic scale (difficult to be combined with other materials in wet environment). Very flammable. |
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Term
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Definition
the most expensive engineering material. May only be forged, not magnetic and high temp resistant.
Comparable to medium carbon steel (tensile)
Used in space and aeronautical industry |
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Term
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Definition
| Compounds of mixtures of oxides, carbines, borides, and nitrides of metals. Too hard to be machined, the come in the form of powdered material that is compacted and sinterized to form the final product. Ceramics have very high hardness and brittlenss. They are light weight, low cost and have very good corrosion and igh temperature resistance. |
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Term
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Definition
Include a wide variety of materials consisting of large chains of molecules of organic compounds (polymers)
They are characterized by low density, low strength, low stiffness, low hardness, excellent corrosion resistance and electrical insulators. They have a non-linear strain-stress behavior. |
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Term
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Definition
| could be formed repeatedly by heating and molding. Nylon, acrylic, polycarbonate, polyurethane |
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Term
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Definition
cannot be remolded, they will burn if heated.
Phenolic and polyester |
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Term
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Definition
| designed materials made out of a matrix including different types of fibers. Number of layers and fibers orientation confer specific properties to the composite, like different strengths along differen directions. They are usally light weight offering high strength on specific directions. |
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