Lesson 1: Material Selection Flashcards
Describe hardness.
Hardness is a measure of how easily a material can be scratched or indented.
What is the Ashby Diagram used for?
To compare the ratio between different properties of materials or classes of materials
How is the suitability of a material determined in the materials selection table?
By calculating the sum of (IR x MR) for each class of material
What is the purpose of the Materials Rating (MR) in the materials selection table?
To indicate the desirability of a material’s property for the application
What is the purpose of the Importance Rating (IR) in the materials selection table?
To indicate how important a property is for application
What is the main goal of material selection in product design?
To minimise cost while meeting product performance goals
What is an important consideration when
designing a physical object?
Material selection is an important step in the process of designing any physical object
Define durability
Durability is the combination of strength and toughness in a material
What does thermal conductivity measure?
It measures how well a material can conduct heat
What does electrical conductivity measure?
It measures how well a material can conduct electricity
Explain elasticity
Elasticity is the ability of a material to return to its origincal form after a load has been applied and removed
What is toughness?
Toughness is the ability of a material to withstand shock or sudden impact without breaking. Also a combination of strong and ductile.
Describe the characteristics and properties of metals.
Good electrical and heat conductors, shiny appearance, good tensile and compressive strength, ductile, high toughness
What is fatigue resistance?
It refers to how many repeated cycles of loading and onloading a material can withstand before it fails or breaks.
How does high stiffness affect a material?
It makes a material hard to bend or stretch
What is stiffness (Young’s modulus)?
It is also known as Young’s Modulus, is the ability of a material to resist deformation in repsonse to an applied force.
Define compressive strength.
It is the ability of a material to withstand pushing or squeezing forces. (compression)
Describe tension strength.
It refers to the ability of a material to withstand pulling or stretching forces. (tension)
What is strength in the context of materials?
It refers to the ability of a material withstand applied force.
How would you define ductility?
It refers to how much a material can stretch or deform under loading. A very ductile material can be stretched to great length before it snaps.
What is the definition of density?
Mass of material per unit volume. High density means particles are more densely packed, while low density means particles are more loosely packed.
Can there be a perfect material?
No, there are limitations. Properties can be tailored by combining materials, such as alloys and composites.
Define ceramics and list their characteristics and properties.
Compounds between metallic and non-metallic elements, hard, brittle, poor tensile strength, high compressive stength, electrical insulators, poor thermal conduction, heat and corrosion resistant.
What are the characteristics and properties of polymers?
Non-conductors, low melting point, poor fatigue strength, average toughness, poor tensile and compressive strength.
