Mechanical Properties: These describe how
a material will respond to different types
of external forces
Types of
Strength
Tensile Strength - the
ability to withstand
pulling (stretching) forces
Compressive Strength -
ability to withstand pushing
(squashing) forces
Shear strength - ability to withstand
forces which tend to cut the material
in two
Torsional strength - ability to
withstand twisting (rotary) forces
Bending strength -
ability to resist bending
forces
Hardness - the ability of a material to withstand
indentation or scratching. This is a requirement
when a product or component needs to have good
wear resistance. Examples include twist drills,
chisels, roller bearings and kitchen cutting
surfaces
Elasticity - a measure of how flexible a materials is.
Elasticity is important in products such as vaulting
pols and springs
Malleability - the ability of a material to be
hammered of forged into shape. The
material may be shaped hot or cold
Ductility - the ability of a material to be permanently deformed by
cold-working. This can be achieved by bending, twisted or pulling
materials through a die. Materials for wires need to be ductile. Metals
for car bodies need eo be ductile so that they can be formed when
pressed.
Machineability - this is how easily a material
can be manufactured using machine tools
Toughness - is how well a material can withstand impact forces. The
oppostie of toughness is brittleness. A material is said to be brittle if it
has low resistance to impact loads. Toughness is important for
products such as hammers, machine parts, kitchen utensils, gardening
tools and railway lines
Properties
A property is a
characteristic of a material
A material will possess a
range of different properties
Designers use properties to help them
select a material for a particular
purpose
The range of properties can be divided into
mechanical, physical and aesthetic properties for
both service and manufacture
Aesthetic Properties
Colour
Surface Texture
Surface
Decoration
Brightness
Physical Properties - these
describe how a material will
respond to physical influences
other than force
Optical Properties -
how light can pass
through a material. A
material can be
transparent, translucent
or opaque
Resistance to
corrosion - how well a
material will resist
corrosion. Rusting is
the main form of
corrosion in steels.
Most steels have to be
protected against
rusting
Thermal Conductivity - how well a
material will conduct heat. Soldering iron
tips and saucepans need good thermal
conductivity properties so that they can
transfer heat quickly. Metals are good
conductors of heat.
Electrical conductivity - how well a material
conducts electricity. electrical wires and
terminals need to be good electrical
conductors. Aluminium, copper and silver are
example of good conductors. Insulators are
materials which do not conduct electricity