Materials Ch.1

What is materials science?

Investigating relationships between structures and properties of materials

In which era is todays material age often categorized?

Silicon (Electronic Materials) Age

Why is it important for engineers to understand materials?

To select appropriate materials and processing techniques for specific applications

How does increasing carbon content affect the hardness of steel?

Increases hardness

Which material is typically used for its high thermal and electrical conductivities?

Metals

Which type of material is known for being hard and brittle with low thermal and electrical conductivities?

Ceramics

What is a key characteristic of polymers used in materials engineering?

Soft, ductile, low strengths, and low densities

Why is it important for materials engineers to understand the relationships among processing, structure, and properties?

To ensure that materials perform as required in their intended applications

What types of material can be transparent, translucent, or opaque depending on its structural characteristics?

Polymers and Ceramics

Which of the following is NOT a category of material properties?

Mechanical, Electrical, Photovoltaic, Thermal

Photovoltaic

What happens to the thermal conductivity of cooper when zinc is added

Decreases

What is the best example of materials processing?
Extrusion, Crystalline, Amorphous, Glassy, Elastic Modulus

Extrusion

Which is the best example of a material structure?

Single-phase, Elastic Modulus, Sintering, Magnetic Permeability, Brittle

Single-phase

Which class of materials is generally associated with the highest density values at room temperature?

Metals

What increases electrical resistivity?

Increasing temperature, increasing impurity content, deformation

Classify ZrO₂

Ceramic

What type of molecular structure of alumina is the most transparent?

Single crystal has a high degree of structural perfection

Perfect structure = perfect clarity

Which metal has the highest electrical conductivity?

Silver

What is the most thermally conductive material?

Diamond

How many materials do materials engineers typically have to choose from for various applications?

160,000

Which is NOT a common property of a metal?

Conductivity, Strength, Tendency to corrode, Light weight

Light weight

What is a combination of 2 elements in a certain proportion called?

Compound

Which one of these is NOT a ceramic?

Glass, Tungsten Carbide, Teflon, Porcelain

Teflon

What phenomenon occurs when a material is both stressed and exposed to a corrosive environment, leading to the formation of small cracks?

Stress-corrosion cracking

What is the effect of adding 3 atomic % silicon to iron?

Improves its performance as a recording medium by enhancing its magnetic properties.

Which material is known for having significant void space and low thermal conductivity, making it suitable for space shuttle insulation?

Ceramic fibers

What do materials engineers do?

create products from existing materials

develop materials processing techniques

What caused the Challengers disaster?

on launch day, the temperatures were colder then expected

rubber became less flexible

o-rings did not expand properly to seal gap between segments

hot gasses and chemicals leaked and exploded fuel tank

What caused the fails of the Liberty ship and the Titanic?

when ductile metals are cooled they can become brittle and experience brittle fracture

What is todays material age?

Silicon (electronic materials) Age

What was the nanomaterial age?

when we began to observe on a nanometer scale

What was the polymer age?

age of plastics; lightweight, easy manufacture, and coloring

What are polymers composed of?

non-metallic elements

What are ceramics composed of?

compound of metallic and non-metallic element

Rank metals, polymers, and ceramics from strongest to softest.

Metals, Ceramics, Polymers

Which are ductile and which are brittle: metals, polymers, and ceramics

ductile: polymers, ceramics

brittle: metals

Thermal and electrical conductivities of metals, polymers, and ceramics (low or high)?

Metals: high

Polymers: low

Ceramics: low

We know all metals, polymers, and ceramics are opaque, but are each reflective or translucent and transparent?

Metals: reflective

Polymers: translucent and transparent

Ceramics: translucent and transparent

What happens when you increase carbon content of some common steel?

hardness increases

What happens to resistivity when you increase temperature of copper?

resistivity increases

What happens to resistivity when you increase the impurity content of copper?

resistivity increases

What happens to resistivity when you increase deformation of copper?

resistivity increases

What is thermal conductivity?

materials ability to conduct heat

What happens to thermal conductivity if you increase impurity content?

decrease in thermal conductivity

Describe a single crystal/crystalline structure. How does it appear optically?

high degree of perfection

optically transparent

Describe a polycrystalline structure. How does it appear optically?

having small grains and different alignments

optically translucent

How can you diminish the rate of crack growth?

Heat treating

What are all the categories that most properties of materials fall into?

Mechanical, electrical, thermal, magnetic, optical, deteriorative