ES195 - Materials selection for engineering Flashcards
1
Q
Families of materials
A
- Glass
- Elastomers
- Metals/Alloys
- Ceramics
- Polymers
(Gorillas eat many Chinese pedophiles)
2
Q
Material properties
A
- Chemical - reactivity, corrosion, oxidation
- Life-cycle - availability, formability, recyclability
- Physical - optical, electrical, magnetic
- Structural - strength, stiffness, toughness
- Thermal - expansion, conduction, heat capacity
(* Other - aesthetics, ergonomics, desirability)
(CLP-ST)
3
Q
Factors in material design choice
A
- Function - related to material properties
- Commercial - availability of raw materials, required manufacturing volumes, logistics
- Environmental - impact of different materials (embodied energy, pollutants)
4
Q
Design requirements
A
- Function - what does the component do
- Constraints - what conditions must be met
- Objectives - what must be maximised/minimised
- Free variables - which design variables are free
5
Q
Material selection process
A
- Translation - Express design requirements as constraints and objectives
- Screening - Eliminate materials based on constraints and objectives
- Ranking - Rank materials based on derived performance indices describing best performance
- Refining - Use additional information to refine selection
6
Q
Crystalline/Polycrystalline
A
Long range order
7
Q
Amorphous
A
Short range order
8
Q
Types of secondary bonding (weak)
A
- Van der Waals forces - dipolar attraction between uncharged atoms
- Hydrogen bonding - dipole attraction between bonded hydrogen and adjacent ions
9
Q
Strengthening sources in polycrystalline materials
A
- Atomic bonding
- Crystal structure
- Solid solution strengthening (i.e. alloying of metals)
- Work hardening (i.e. mechanically induced microstructural defect that resists further deformation)
- Precipitation hardening (i.e. typically hard secondary phases that inhibit deformation of the bulk material)
