4.1 Properties of materials | IB Design Technology

physical properties

physical properties

characteristics of materials that can be identified through non-destructive testing

mass

A measure of how much matter is in an object

weight

A measure of the force of gravity on an object's mass

volume

the quantity of 3-dimensional space within an object

density

the mass per unit volume of a material

electrical resistivity

The measure of a material's ability to resist electricity, measure of opposition to the flow of current. (i.e. low resistivity materials will conduct electricity well)

thermal conductivity

a measure of how fast heat is conducted through a slab of material

thermal expansion

a measure of the degree of increase in dimensions (length, area or volume) when an object is heated

hardness

a material's resistance to penetration or scratching

tensile strength

a material's ability to withstand pulling forces

compressive strength

a material's ability to withstand being pressure.

ductility

the ability of a substance to be extruded into a wire

stiffness

a material's resistance to deflection by applied force

toughness

A material's ability to absorb energy, can't be fractured, ripped or torn. example: super alloy - high thermal resistivity

plasticity

a material's ability to be changed in shape permanently

elasticity

ability of a material to return to its original shape after some form of deformation.

Youngs Modulus

a measure of the stiffness of an elastic modulus

stress

force / cross-sectional area (force per unit area by applying tensile force)

strain

extension / stretched length (force per unit length after tensile force is applied)

aesthetic characteristics

features related to the appreciation of beauty of form- taste, smell, appearance, texture

properties of smart materials

photo-chromicity, thermo chromic, thermoelectricity, magneto-rheostatic, electo-rheostatic, piezo electricity, shape memory333

photo-chromicity

a material that has reversible change of colour when exposed to light

thermoelectricity

Electricity generated by heat and differences of temperature in materials,

magneto-rheostatic and electo-rheostatic materials

fluid which can experience dramatic change in their viscosity

Piezo electricity

pressure from deformation gives off small electrical discharge

shape memory

metals that exhibit pseudo-elasticity and shape memory due to rearrangement of molecules in the material without temperature change