Materials Science Quiz

What do cooling curves help identify in phase diagrams?

• The melting point of pure metals

• Liquidus and solidus lines

• The density of alloys

• The electrical resistance of materials

What is the main difference between phases and components in alloys?

• Phases are physical states, while components are chemical elements

• Phases are chemical elements, while components are physical states

• Phases are always solid, while components are always liquid

• Phases are mixtures, while components are pure substances

What does the X-axis represent in a phase diagram for alloys?

• Temperature

• Pressure

• Composition (e.g., % copper, % nickel)

• Time

What does equilibrium refer to in material science?

• A material that is uniform throughout.

• A region with uniform properties and structure.

• A stable state where the phases and their proportions do not change over time.

• A material with visibly different parts or phases.

What is one of the main reasons alloys are created?

• To reduce weight

• To improve strength

• To increase cost

• To decrease conductivity

What is the state of an alloy below the solidus line?

• Fully solid

• Partially solid

• Fully liquid

• Partially liquid

What happens to a copper-nickel mixture when it solidifies?

• It forms multiple phases.

• It forms a single, homogeneous phase.

• It separates into copper and nickel layers.

• It becomes a gas.

How is "heterogeneous" best defined?

• A material with visibly different parts or phases, like a mixture with separate regions.

• A region within a material that has uniform physical and chemical properties.

• A material uniform throughout, like a solution where all parts are the same.

• A stable state where a system's properties, like phase proportions, do not change over time.

What does "homogeneous" mean?

• A material with visibly different parts or phases, like a mixture with separate regions.

• A region within a material that has uniform physical and chemical properties.

• A material uniform throughout, like a solution where all parts are the same.

• A stable state where a system's properties, like phase proportions, do not change over time.

Why might an engineer choose an alloy over a pure metal for a particular application?

• Alloys are generally more expensive than pure metals.

• Alloys often have enhanced properties like strength and corrosion resistance.

• Pure metals are always stronger than alloys.

• Alloys are more difficult to work with than pure metals.