Ch.4 Materials Key Terms Flashcards
Alloy
A metal produced by mixing other metals.Developed to improve properties not found on the original metal. Examples: Steel-Carbon and iron
Bronze-Copper and Tin
Composite
Materials that combine two or more other materials to form a new material. Can be natural or synthetic. Examples: Concrete-Cement, gravel, rocks, water
Wood- Cellulose fibers and resin
Carbon Fiber
Density
The degree of consistency measured by the quantity of mass per unit volume (kg/m^3).
Electrical Resistivity
The measure of the ease with which free electrons move through a material. High resistivity means it is difficult to move.
Thermal Conductivity
Measure of the efficiency with which thermal energy will travel through a material.
Generally, materials that conduct electricity well, conduct heat well.
Thermal Expansion
When materials are heated they gain thermal energy.
This energy leads to an increase in atomic vibrations and atomic separation.
Therefore the overall dimensions of the part increase.
Hardness
The resistance of a material to scratching, penetration or cutting.
There are multiple “Hardness Scales”. Some include:
Brinell
Rockwell
Vickers and
Mohs
Tensile Strength
A measure of a material’s resistance to deformation from a tensile or stretching load.
Stiffness
A material’s resistance to deflection.
Toughness
The ability of a material to resist the propagation of cracks.
Ductility
The ability of a material to undergo plastic deformation by the application of tensile forces.
If a material can be drawn into a wire, it is ductile.
Think of stretching taffy candy.
Laminated timber
Wood cut into thin sheets of 2-3mm called veneers.
Veneers are glued back together with the grains being perpendicular to the sheet above it.
Produces a very strong sheet of timber.
Commonly called plywood.
Particle Board
Manufactured by gluing small flakes, chips or pieces of timber together under pressure.
Chipboard is a common example
Cheap to manufacture
Can have decorative veneers added.