Microstructure & Alloys Flashcards
How does a lattice structure affect a metal?
Determines the strength and deformation.
If bonds between metal atoms break it causes a ___?
Fracture
Describe a body centred cubic arrangement.
One atom at each corner and one in centre of cube.
What property do body centred cubic structures possess and what is an example?
BCC’s are very stiff and an example would be iron.
Describe a face centred cubic structure.
An atom at each corner plus an atom on each face bruh.
What property do face centred cubic structures possess and what is an example?
FCC’s are often soft and ductile, and an example would be copper or aluminum.
The three type of lattice defects are? (PLC)
Point, Line, Surface
A Type 1 (Vacancy) Point Defect is?
A lattice site missing an atom, so for example it would be like a FCC without an atom on one of the faces.
A Type 2 (Intersittal) Point Defect is?
An extra, usually smaller atom, not at a lattice site. So for example it would be like a BCC with a 2 atoms in the middle.
A Type 3 (Substitutional) Point Defect is?
An atom within the lattice is replaced with a foreign atom. So for example it would be like an FCC with a small atom on one of the corners.
Line Defects occur when?
Solidification when metal is plastically deformed.
A Line defect is what?
An extra plane of atoms inserted into a perfect structure. (YOU aint supposed to be there bruh get back in line)
What are 2 examples of Surface defects?
Crystals form at random sites, and crystals randomly orientate.
What are the consequences of Surface Defects?
- Grains will have identical structure but different orientation
- Grain Boundaries will form that hinder dislocation and movement.
What turns iron into steel?
The Carbon content.
What Carbon percentage is steel bruh?
0.02-2.11
Low (Plain) alloy steel contains what percentage of alloy compounds?
less than 5%
High Alloy steels have what percentage of alloy compounds?
Greater than 5%
What carbon percentage is cast iron?
2.11-6.7%
What Three properties influence the mechanical properties of steel? (CIT)
- Carbon Content
- Impurities
- Treatment
Steel with high carbon contents will have what in regards to strength ductility and toughness?
High strength and ductility, Low toughness
Nickel alloys will have what in regards to strength ductility and toughness?
High strength, ductility, toughness.
Chromium alloys will have what in regards to hardness, strength and corrosion?
High hardness and strength, low corrosion
Copper alloys will have what in regards to ductility, strength and corrosion?
High ductility and strength, high corrosion
Too much manganese alloy and your metal is?
brittle
What does heat treating a metal do?
- Changes microstructure of material
2. Can change strength ductility, toughness, hardness.
What happens during annealing of steel?
Heat to temp above critical value, hold temp constant and slow cool.
What is purpose of annealing?
Coarsen the grain structure which decreases strength but increase ductility and toughness.
What happens when you normalize steel?
similar to annealing but you allow the steel to cool in air
What is the purpose of normalizing steel?
Refine the grain structure to produce tough and hard materials.
What happens during quenching (Hardening) of Steel? (Martensite Structures)
Cool steel rapidly
What is the purpose of quenching?
Makes extremely fine grain structure which increases strength and hardness but makes extremely brittle.
What happens during tempering?
You reheat the quenched steel.
What is the purpose of tempering?
Increase toughness, increase strength and ductility.
