Quiz on Phase Diagrams and Reactions

Which of the following best describes the process of solidification in metals?

• Increase in temperature with constant pressure

• Transition from solid to gas phase

• Nucleation and growth of crystals as liquid transforms to solid

• Disappearance of grain boundaries

In the cooling curve of a pure metal, the horizontal portion represents:

• Decrease in temperature during solid state

• Supercooling before solidification starts

• Latent heat release during phase change

• Complete cooling of the metal

Which of the following statements is true about alloy cooling curves?

• Alloys solidify at a single temperature

• Cooling curves of alloys show a constant temperature during solidification

• Alloys exhibit a temperature range during solidification

• Alloys do not release latent heat

A "phase" in a material system refers to:

• The melting point of a metal

• A region with uniform physical and chemical properties

• A cooling curve region

• The point where solidification begins

What does a phase boundary in a phase diagram indicate?

• Area of highest temperature

• Interface between two similar phases

• Conditions under which two or more phases coexist

• Maximum solubility of impurities

What is the formula for Gibbs's Phase Rule?

• F = C + 2

• F = C + P - 2

• F = C - P + 2

• F = C - P

For a binary system with two phases in equilibrium, the degrees of freedom are:

• 0

• 1

• 2

• 3

Lever’s Rule is used to:

• Determine the melting point of alloys

• Calculate the mass fractions of phases at equilibrium

• Identify invariant points in a phase diagram

• Measure cooling rates of metals

An isomorphous binary system is characterized by:

• A eutectic point

• A peritectic reaction

• Complete solubility of components in both liquid and solid states

• No solubility in either phase

In the Lead-Tin (Pb-Sn) system, the eutectic composition solidifies at:

• A constant temperature

• A temperature range

• Multiple points

• Room temperature