AIT Material Science 2 — Questions and Answers
Question 1: Which heat treatment process involves heating steel above its critical temperature and then cooling it slowly in the furnace to reduce hardness?
- Annealing (Correct answer)
- Quenching
- Tempering
- Normalizing
Correct answer: Annealing
Annealing involves heating steel above its critical temperature and slow furnace cooling to relieve stresses and reduce hardness.
Question 2: What property describes a material's ability to return to its original shape after the applied stress is removed?
- Plasticity
- Elasticity (Correct answer)
- Ductility
- Malleability
Correct answer: Elasticity
Elasticity is the ability of a material to recover its original shape and size when the deforming force is removed.
Question 3: Which type of cast iron contains graphite in a flake form, making it brittle but with excellent compressive strength?
- Malleable cast iron
- Ductile cast iron
- Gray cast iron (Correct answer)
- White cast iron
Correct answer: Gray cast iron
Gray cast iron contains graphite in flake form, which gives it high compressive strength but low tensile strength and brittleness.
Question 4: What is the purpose of the carbon content in steel alloys for trade applications?
- To increase corrosion resistance
- To reduce melting point
- To control hardness and strength (Correct answer)
- To improve electrical conductivity
Correct answer: To control hardness and strength
Carbon content in steel primarily controls its hardness, strength, and hardenability through heat treatment processes.
Question 5: Which bonding type is responsible for the high melting points and hardness of ceramic materials?
- Metallic bonding
- Van der Waals forces
- Ionic and covalent bonding (Correct answer)
- Hydrogen bonding
Correct answer: Ionic and covalent bonding
Ceramics have high melting points and hardness because of strong ionic and covalent bonds between their atoms.
Question 6: A material that fractures without significant plastic deformation before the breaking point is described as:
- Ductile
- Malleable
- Brittle (Correct answer)
- Resilient
Correct answer: Brittle
Brittle materials fracture suddenly with little or no plastic deformation when stressed beyond their elastic limit.
Question 7: What is the term for the gradual deformation of a material under constant stress over time, especially at elevated temperatures?
- Fatigue
- Creep (Correct answer)
- Wear
- Corrosion
Correct answer: Creep
Creep is the slow, time-dependent plastic deformation of a material under sustained load, especially significant at high temperatures.
AIT Material Science 2
Which heat treatment process involves heating steel above its critical temperature and then cooling it slowly in the furnace to reduce hardness?