topic 2 Flashcards
(31 cards)
What are physical properties?
How a material behaves in response to non-mechanical forces (e.g. heat, electricity, moisture)
Physical properties include characteristics such as density, fusibility, conductivity, thermal expansion, absorbency, and opacity/transparency.
Define density in materials.
Mass per unit volume – high density = heavy (e.g., metals), low = lightweight (e.g., polymers)
Density is a crucial factor in determining the weight and suitability of materials for various applications.
What is fusibility?
Ability to melt and join with another material when molten (important in casting/welding)
Fusibility is essential for processes like welding and casting where materials need to bond together.
What does conductivity refer to in materials?
Transfer of energy (thermal or electrical) – metals = good conductors
Conductivity is a key property for materials used in electrical and thermal applications.
What is thermal expansion?
How much a material expands when heated – critical in precision engineering
Understanding thermal expansion is vital to avoid material failure in applications involving temperature changes.
Define absorbency in materials.
Ability to absorb moisture (natural fibres absorb more than synthetic ones)
Absorbency is important for textiles and materials used in environments where moisture is present.
What does opacity/transparency mean in materials?
How much light passes through a material – glass is transparent, wood is opaque
This property affects the aesthetic and functional applications of materials.
What are mechanical properties?
How a material behaves under force
Mechanical properties include tensile strength, compressive strength, shear strength, toughness, hardness, malleability, ductility, elasticity, plasticity, and brittleness.
Define tensile strength.
Resistance to being pulled apart
Tensile strength is crucial for materials used in applications where stretching or pulling forces are present.
What is compressive strength?
Resistance to being squashed
Compressive strength is important for materials used in construction and structural applications.
Define shear strength.
Resistance to sliding forces acting in opposite directions
Understanding shear strength is essential in applications involving layered materials or connections.
What does toughness refer to in materials?
Resistance to impact and sudden force – doesn’t shatter easily
Toughness is important for materials that need to withstand sudden impacts without breaking.
Define hardness in materials.
Resistance to scratching, cutting, or wear
Hardness is a critical property for tools and surfaces that experience friction.
What is malleability?
Ability to deform under compression without cracking
Malleability is a key property for metals used in forming processes like rolling and forging.
Define ductility.
Ability to be drawn out into a wire without breaking
Ductility is essential for materials used in electrical wiring and other applications requiring stretching.
What does elasticity mean in materials?
Ability to return to original shape after stretching or compression
Elasticity is important in applications where materials undergo repeated stress.
Define plasticity in materials.
Ability to permanently deform without breaking
Plasticity is crucial for processes that require shaping materials without failure.
What is brittleness?
Breaks easily without deformation – opposite of toughness
Brittleness is a critical consideration in materials that must withstand impact.
What is tensile testing?
Pulling a material to see when it breaks
An example includes comparing nylon vs steel wire.
What does hardness testing measure?
Using a file, scratch test, or indentation
Methods include the Mohs scale and Brinell test.
What does a toughness (impact) test evaluate?
Hitting a material to see if it shatters
Common tests include Charpy or Izod impact tests.
What is a malleability test?
Bending a sample to see if it cracks
This test is often used for metals like copper.
What does a ductility test assess?
Pulling wire to see how thin it can get
This test is common in electrical wire production.
What does a thermal conductivity test measure?
Measuring how fast heat moves through a material
An example is comparing metal vs plastic handles.
