chapter 2 material science

solvent

• In an alloy, the element or compound present in lesser amount.

• Degree to which the two components mix.

• The elements or compounds which are mixed initially

• In an alloy, the element or compound present in greater amount.

What happens during solidification of a pure metal?

• Liquid turns into gas

• Atoms rearrange into a crystalline structure

• Metal evaporates

• Atoms break down

Answer explanation

Solidification is the transformation from liquid to solid where atoms form a crystalline structure.

Which factor has the greatest effect on grain size?

• Density

• Pressure

• Cooling rate

• Color of metal

Answer explanation

Faster cooling forms smaller (fine) grains; slower cooling forms coarse grains.

Alloys solidify over:

• One temperature

• A range of temperatures

• Fixed time only

• Constant pressure

Answer explanation

Alloys usually do not have a single melting point, unlike pure metals.

Why are fine grains preferred in metals?

• Cheaper to produce

• Reduce density

• Increase strength and toughness

• Improve corrosion

Answer explanation

Fine grains block dislocation motion better, improving mechanical strength.

A binary phase diagram shows the relationship between:

• Pressure and hardness

• Strength and ductility

• Temperature and composition

• Color and melting point

What is the eutectic point?

• Where material evaporates

• The highest melting temperature

• The lowest temperature where liquid can exist

• Where ductility is maximum

The lever rule helps in determining:

• Number of atoms in alloy

• Mass of sample

• Amount of each phase present

• Grain size

A tie-line is used in a binary phase diagram to:

• Connect liquid and gas phases

• Show energy levels

• Determine phase proportions

• Predict corrosion rate

The eutectic reaction results in:

• Two solids transforming into liquid

• Liquid transforming into two solids

• Solid becoming liquid

• Solid forming gas