4.2 Performance of Metals

Question 1

What are the mechanical properties for metals?

Answer 1

• Hardness
• Toughness
• Malleability
• Elasticity
• Tensile strength

Question 2

Are alloys or pure metals usually stronger? Explain why

Answer 2

Alloys are usually stronger, asthey have different sized atoms which mean they are less able to slide over one anothermaking the metal harder

Question 3

Which are the hardest metals?

Answer 3

Tungsten and titanium

Question 4

Why is mild steel used in the manufacture of car bonnets?

Answer 4

• Mild steel is strong and durable to withstand stresses and impacts, such as minor collisions and road debris
• Mild steel is relatively easy to form and shape, allowing manufacturers to create complex curves and contours

Question 5

Which metals are most malleable?

Answer 5

Gold, silver, aluminium and copper

Question 6

Which metals are most ductile?

Answer 6

Gold, silver, copper and aluminium

Question 7

In what ways can the stength of metals be measured?

Answer 7

• Compressive strength
• Tensile strength
• Bending strength
• Torsional strength
• Shear strength

Question 8

What is compressive strength?

Answer 8

the ability to withstand being crushed or shortened by pushing forces

Question 9

What is tensile strength?

Answer 9

It is the ability to resist stretching or pulling forces

Question 10

What is bending strength?

Answer 10

It is the ability to resist forces that may bend the material

Question 11

What is torsional strength?

Answer 11

It is the ability to withstand twisting forces from applied torque or torsion

Question 12

What is shear strength?

Answer 12

The ability to resist sliding forces on a parallel plane

Question 13

What are two metals that have relatively low densities?

Answer 13

Aluminium and titanium

Question 14

What are the physical properties for metals?

Answer 14

• Density
• Melting points
• Thermal conductivity
• Electrical conductivity
• Resistance to corrosion
• Ability to take coatings and finishes
• Ability to be alloyed and joined with heat processes

Question 15

List three different applications of copper where thermal conductivity is important

Answer 15

• Cookware, as it is essential that heat is distributed evenly across the cooking surface, preventing hot spots and ensuring uniform cooking
• Electrical wires, as conducts heat away from wires, preventing overheating and ensuring safety
• Plumbing Systems, as it allows hot water to reach taps and fixtures quickly while minimizing energy losses in hot water distribution

Question 16

Which metal has the highest melting point?

Answer 16

Tungsten at 3422°C

Question 17

Which metals have very low melting points?

Answer 17

• Mercury (at -38.9°C)
• Pewter (at 170–230 °C)
• Tin (at 232°C)
• Lead (at 327.5°C)

Question 18

Which metal has the best electrucal conductivity?

Answer 18

Silver (Copper also has good conductivity and is more cost effective)

Question 20

What makes makes titanium ideal for use in hip and knee replacements?

Answer 20

• It is highly resistant to corrosion, reducing the risk of adverse reactions within the body
• It has a strong and durable structure, able to withstand the mechanical stresses associated with joint replacements
• Despite its strength, titanium is relatively lightweight, contributing to patient comfort and mobility

Question 21

Why is Aluminium suitable for a drinks can?

Answer 21

• It’s malleable which allows the can to be deep drawn into shape
• It’s lightweight- easier to transport, adds little to the product weight
• It’s a food safe material
• It’s non-ferrous so won’t rust on contact with the liquid in the can
• Easy to recycle and use for other products (low melting point)

Question 22

What makes brass suitable for use in a trumpet?

Answer 22

• It is malleable, easy to shape and machine, allowing for intricate designs that contribute to the trumpet’s unique sound and structure
• Brass has good corrosion resistance, as it is exposed to moisture from breath