Chapter 2

Question 1

Types of ferrous and nonferrous

Answer 1

Ferrous - Steel and cast iron

Nonferrous - aluminum and copper

Question 2

Four types of steel

Answer 2

Plain carbon steel
Low alloy steel
Stainless Steels
Tool Steels

Question 3

Plain carbon steel. Explain strength and ductility.

Answer 3

Mainly carbon. Strength increases with carbon but ductility decreases. Heat treated will make martensite which is very strong and hard.

Question 4

Plain carbon steel. Explain use of low, medium, and high carbon steel.

Answer 4

Low carbon (<0.20%) - railroad rails
Medium carbon (0.20% to 0.50%) - Machinery components.
High Carbon (>0.50%) - Springs, and cutting tools and blades

Question 5

Low alloy steel

Answer 5

Superior to plain carbon steel after heat treatment. High strength, hardness, hot hardness,

Question 6

Stainless Steel

Answer 6

15% Chromium. Nickel protects against corrosion. Carbon adds strength and hardness but reduces corrosion protection.

More expensive than low alloy and plain C.

Question 7

Tool steels

Answer 7

Highly alloyed. Heat treated. For dies and molds.

Question 8

Properties of Nickel and alloys

Answer 8

Magnetic. Modulus of E close to iron. Superior when heat treated. Very corrosive resistant.

Question 9

Properties of Zinc and alloys

Answer 9

Low melting temp so for die casting. Corrosion protection as coating.

Question 10

Properties of Superalloys

Answer 10

Resist surface degradation at high temperature. Very expensive. Gas turbines
Meant for 1100 C temp.

Question 11

What are new Ceramics

Answer 11

Controlled simple structures.

oxides, carbides, nitrides, and borides.

Question 12

Oxides ceramics. Properties

Answer 12

Al2O3 or Alumina.

Good hot hardness, low thermal conductivity, and good corrosive resistance

Question 13

Carbide ceramics

Answer 13

Silicon Carbide and tungsten carbide

Cutting tools

Question 14

Properties of Nitrides

Answer 14

Silicon nitride and boron nitride
Hard, brittle, high melting temperature, electrically insulating.

Gas turbine components and cutting tool coatings

Question 15

Glass properties

Answer 15

State of matter - Not enough time to cool from molten state to crystalline structure.

Type of ceramic - Inorganic nonmetallic that cools to a rigid condition without crystallizing.

Question 16

Main component of Glass

Answer 16

SiO2. Silica. 50% to 70%

Naturally transforms into a glassy state when cooling instead of crystallization like other ceramics.

Question 17

Why add ingredients to glass

Answer 17

Adds color, acts as flux (promotes fusion), alter index of refraction for optics, and decreases viscosity

Question 18

Polymer and properties

Answer 18

Organic long-chain molecules.

Low density. good strength to weight. high corrosion resistance. low electrical and thermal conductivity.

Question 19

Types of Polymers

Answer 19

Plastics - thermosetting and thermoplastic

Rubber - elastomers

Question 20

Thermoplastics

Answer 20

Polyethylene and nylon. Solid at ambient temp but liquid at ~100 degrees. No degradation after cycles of cooling and heating.

Question 21

Thermosettings

Answer 21

Phenolics and epoxies. Degrades (char) after repeated heating cycles. When heated they flow and shape around mold. Elevated temp cause chemical reaction making it in-fusible.

Question 22

Elastomers

Answer 22

Rubbers. Extreme elastic extensibility (factor of 10) under relatively low mechanical stress.

Similar structures to thermosets but different properties. Both different to thermoplastics.

Question 23

Importance of Polymers. 4 traits.

Answer 23

Net shape processing.
Cost competitive.
Require less energy to produce than metals.
Transparency competes with glass.

Question 24

Name polymer molecular structure

Answer 24

Linear (chain link), Branched (chain link but with branches), cross-linked (elastomers are loose; thermosets are tight)

Question 25

Composite properties

Answer 25

Very strong and stiff yet light in weight.
Large toughness
Great fatigue properties

Question 26

What are primary and secondary phases

Answer 26

Primary - The matrix when the secondary phase is embedded

Secondary - Reinforcing phase that reinforces the primary phase.

Question 27

Reinforcing agent

Answer 27

It strengthens the material which as a fibers, particles or flakes.

Question 28

Downsides to Polymers

Answer 28

Low strength
Low modulus of elasticity or stiffness
Service temperature range limited to a few hundred degrees
Degrade due to sunlight and other forms of radiation