Metals Flashcards
(13 cards)
metal definition
aggregate of atoms in crystalline structure
alloy definition
combination of metal atoms in crystalline structure
fracture strength
The maximum stress a material can withstand before breaking.
elastic limit
The maximum stress a material can take and still return to its original shape once the stress is removed.
ductility
The ability of a material to stretch or deform without breaking (e.g. how much it can bend or be drawn into a wire).
compressive strength
The ability of a material to resist being squashed or compressed.
hardness
The resistance of a material to being scratched or indented.
describe cold working/work hardening
adv
disadv
shaping a metal at low/root temperature [below recrystallisation]
causes slip = dislocations collect at boundaries
improves strength, harness, elastic limit, tensile strength
decreases ductility, corrosion resistance, impact resistance, causes internal stresses
what is residual stress and how is it relieved
instability after shaping/cold working
results in distortion over time
relieved via annealing
what is annealing
heating metal/alloy
migration and rearrangement of grains
removes instability
how does crystal grow
atoms act as nuclei of crystallisation
crystals grow to form dendrites
in lattice network
what is slip
dislocation of columns where a force is applied and defect move along = propagation
defect collects at grain boundary and lattice changes shape to new one free from imperfection
what is quenching
fast cooling
way to alter crystals
