Material Science and Engineering: An Introduction, 10th Edition

What are the six property classifications of materials ?

What are the six property classifications of materials ?

1. Mechanical Properties
2. Thermal Properties
3. Electrical Properties
4. Magnetic Properties
5. Optical Properties
6. Chemical Properties

What are the four components involved in the materials design, production, and utilisation process?

1. Materials properties: Understanding the characteristics of materials is essential for selecting the right material for a specific application
2. Materials processing: This involves shaping and forming raw materials into the desired product or structure
3. Structure: The microstructure and macrostructure of materials significantly influence their properties and performance
4. Performance: The final products performance determines how well it fulfils its intended function

What are the three important criteria in the materials selection process?

1. Mechanical properties: Materials should have the necessary strength, toughness, and other mechanical properties for their intended application
2. Cost: The cost of materials and their processing should be within budget constraints
3. Environmental impact: Consider the ecological footprint and sustainability of materials throughout their life cycle

What are the three primary classifications of solid materials and their distinctive chemical feature?

1. Metals: Characterised by their high electrical conductivity and malleability
2. Ceramics: Known for their high melting points and excellent heat resistance
3. Polymers: Made up of long chains of repeating molecules (monomers) and have a wide range of properties depending on their structure

What are the four types of advanced materials and their distinctive feature(s)?

1. Composites: Combinations of two or more materials with difference properties, resulting in enhanced performance and tailored characteristics
2. Semiconductors: Materials with electrical conductivity between conductors and insulators, crucial for electrical and computing.
3. Biomaterials: Materials designed for use in medical application, compatible with biological systems
4. Smart materials: Capable of changing their properties in response to external stimuli, like shape memory alloys or piezoelectric materials

What is the definition of smart material/system?

A smart material or system is a material that can sense changes in its environment and respond by adapting its properties to these changes. This adaptive behaviour allows smart materials to perform specific functions without the need for external control

What is the concept of nanotechnology as it applies to materials?

Nanotechnology involves manipulating and controlling materials at the nanoscale level, typically within the range of 1 to 100 nanometers. At this scale, materials can exhibit unique properties and behaviours, leading to innovations in various fields, including materials science, electronics, and medicine.

What is the historical significance of materials in human development?

The development and advancement of societies have been closely linked to their ability to product and manipulate materials to meet their needs. Early civilisations were identified by their materials development, such as the Stone Age, Bronze Age, and Iron Age

How did early humans expand their access to materials?

Initially, early humans had access to limited naturally occurring materials, such as stone, wood, clay and skins. Overtime, they developed techniques for producing materials with superior properties, such as pottery and various metals. Head treatments and the addition of other substances were also discovered to alter material properties

What empowered scientists to fashion modern materials?

Approximately over the past 100 years, scientists gained an understanding of the relationships between the structural elements of materials and their properties. This knowledge allowed them to create tens of thousands of different materials with specialised characteristics to meet the needs and modern society, including metals, plastics, glasses, and fibers

How has the development of technology been influenced by materials?

Many technological advancements and the comfort of our modern existence are closely associated with the accessibility of suitable materials. Advancements in understanding specific material types often pave the way for stepwise progression in technology. For example, the availability of inexperience steel or semiconducting materials enabled the development of automobiles and sophisticated electronic devices respectively.

How is materials science different from materials engineering?

Materials science investigates the relationships between the structures and properties of materials, while materials engineering involves designing the structure of material to produce specific properties based on these correlations

What are the difference levels of materials structure ?

1. Subatomic structure: Deals with electrons within individual atoms and their interactions with the nuclei
2. Atomic structure: Relates to the organisation of atoms to form molecules or crystals
3. Nanostructure: Involves appreciates of atoms that form particles (nanoparticles) with nanoscale dimensions (less than about 100nm)
4. Microstructure: Refers to structural elements observed using a microscope, with dimensions between 100nm and several millimetres
5. Macrostructure: Involves structural elements visible to the naked eye, with dimensions ranging from several millimetres to a meter

Name the six different categories of solid material properties ?

1. Mechanical: Relate deformation to an applied load or force (eg. elastic modulus, strength, and resistance to fracture)
2. Electrical: Influenced by an applied electric field (eg. electrical conductivity and dielectric constant)
3. Thermal: Related to changed in temperature or temperature gradients (eg. Thermal expansion and heat capacity)
4. Magnetic: Depends on the response to an applied magnetic field (eg. Magnetic susceptibility and magnetisation)
5. Optical: Electromagnetic or light radiation (eg. Index of refraction and reflectivity)
6. Deteriorative: Chemical reactivity of materials (eg. Corrosion resistance of metals)

How are processing, structure, properties and performance interrelated in materials science?

The processing of a materials affects its structure, which in turn, influences its properties. The material's performance is determined by its properties, and this interrelationship is often depicted in the materials science and engineering paradigm

Why do engineers and scientists study materials?

Engineers and scientists study materials because the things they design are made of materials. Whether its a transmission gear, a buildings superstructure, an oil refinery component, or an integrated circuit chip, various engineering disciplines encounter design problems involving materials

What are some key criteria for selecting materials?

1. In-service conditions: The properties required of a materials are dictated by the conditions it will experience in service.
2. Trade-offs: Rarely does a material possess the ideal combination of properties, so engineers may need to compromise between different characteristics (eg. Strength and ductility)
3. Deterioration considerations: Material properties may degrade during service due to factors like elevated temperatures or corrosive environments
4. Economics: The cost of the finished product, including material expense and fabrication costs, is a critical consideration

What is familiarity with materials important for engineers and scientists?

Being familiar with various characteristics, structure-property relationships, and processing techniques of materials makes engineers and scientists more proficient and confident in making appropriate material choices based on specific criteria

What is the case study on Liberty Ships about?

The liberty ship case study discusses the failure of World War II ships due to brittle fracture of steel that was believed to be ductile. Materials scientists and engineers analysed these fail.urges, determined the causes, and proposed measures to prevent future incidents

What contributed to the failure of some Liberty Ships?

1. Ductile-to-brittle transition: The steel used in these ships experienced a ductile-to-brittle transition at relatively low temperatures, causing brittle fracture in cold environments, such as frigid North Atlantic
2. Stress concentration: The square corners of each hatch acted as stress concentration points where cracks could form
3. Welding vs. Riveting: The shift to welding instead of traditional riveting introduced crack-propagation issues in welded structures
4. Weld defects: Inexperienced operators introduced weld defects and discontinuities, creating potential sites for crack formation

What were the remedial measures taken to address the Liberty ship failures?

1. Improving steel quality: The ductile-to-brittle temperature was lowered by enhancing steel quality, such as reducing sulfur and phosphorus impurity contents
2. Rounding off hatch corners: Curved reinforcement strips were welding onto hatch corners to reduce stress concentration points
3. Crack-arresting devices: Riveted straps and strong weld seams were installed to halt propagating cracks
4. Improving welding practices: Measures were taken to enhance welding techniques and establish welding codes

How are solid materials classified?

Solid materials are grouped into three basic categories: Metals, Ceramics, and Polymers, based primarily on their chemical makeup and atomic structure. Additionally, compositors are engineered combinations of two or more different materials, and there are advanced materials used in high-technology applications

What are the characteristics of metals?

1. Compositions: Metals are composed of metallic elements (eg. Iron, aluminium, copper) and often small amounts of nonmetallic elements (eg. Carbon, nitrogen, oxygen)
2. Atomic arrangement: Atoms in metals and their alloys are arranged in a very orderly manner, resulting in relatively high density
3. Mechanical properties: Metals are relatively stiff, strong and ductile meaning they can undergo significant deformation without fracturing
4. Resistance to fracture: Metals are resistance to fracture, making them widely used in structural applications
5. Electrical and thermal conductivity: Metals are excellent conductors of electricity and heat
6. Appearance: Polished metal surfaces have a lustrous appearance
7. Magnetic properties: Some metals (eg. Fe, Co, Ni) exhibit desirable magnetic properties

What is the difference between metals and metal alloys?

Metals refer to metallic substances composed of one or more metallic elements, while metal alloys are metallic substances composed of two or more elements (including metallic and nonmetallic elements)

What are advanced materials, and give some examples?

Advanced materials are those used in high-technology applications. Examples include semiconductors, biomaterials, smart materials, and nano engineered materials

What are ceramics, and what are they most frequently composed of?

Ceramics are compounds between metallic and nonmetallic elements, with most ceramics being oxides, nitrides, and carbides. Eg. Common ceramic materials include aluminium oxide (alumina), silicon dioxide (silica) silicon carbide, silicon nitride, and traditional ceramics like clay minerals, porcelain, cement and glass

Describe the mechanical behaviour of ceramic materials

Ceramic materials are relatively stiff and strong, comparable to metals in stiffness and strength. They are also typically very hard. Historically ceramics exhibited extreme brittleness and were highly susceptible to fracture. However, never ceramics are engineered with improved fracture resistance, finding applications in cookware, cutlery and automotive engine parts

What are some unique properties of ceramic materials?

1. Electrical and thermal insulators: Ceramics have low electrical conductivities and do not conduct heat well, making them insulative to the passage of heat and electricity
2. High temperature and harsh environment resistance: Ceramics are more resistant to high temperatures and harsh environments compared to metals and polymers
3. Optical characteristics: Ceramics can be transparent, translucent or opaque and some oxide ceramics eg Fe304 exhibit magnetic behaviours

What are some examples of common ceramic objects?

Common ceramic objects include cookware, cutlery and even automobile engine parts

What are polymers and what are they chemically based on?

Polymers include familiar plastic and rubber materials. Many are organic compounds based on carbon, hydrogen and other nonmetallic elements such as oxygen, nitrogen and silicon. They often have large molecular structure with chain like backbones of carbon atoms

What are some common examples of polymers?

Common polymers include polyethylene (PE), nylon, poly (Vinyl Chloride) (PVC), polycarbonate (PC), polystyrene (PS), and silicone rubber

Describe the mechanical characteristics of polymers

Polymers generally have lower densities than metals and ceramics, their stiffnesses and strengths on a per-mass basis can be comparable. Many polymers are extremely ductile and pliable (ie. plastic), allowing for easy forming into complex shapes.

What are some other notable properties of polymers?

1. Chemical inertness: Polymers are relatively inert chemically and unreactive in many environments
2. Electrical conductivity: Polymers have low electrical conductivities
3. Magnetic behaviour: Polymers are no magnetic
4. Temperature limitations: A major drawback of polymers is their tendency to soften and/or decompose at modest temperatures, which can limit their use in certain applications

What is a composite, and what is the design goal of a composite material?

A composite is composed of two or more individual materials from the categories of metals, ceramics, and polymers. The design goal of a composite is to achieve a combination of properties that is not displayed by any single material and to incorporate the best characteristics of each component material

Name two common examples of synthetic composites

Two common examples of synthetic composites are fibreglass, consisting of glass fibres embedded in a polymeric material (usually epoxy or polyester), and carbon fibre-reinforced polymer (CFRP) composites, where carbon fibres are embedded within a polymer

How are composites different from individual materials in terms of properties?

Composites can have a combination of properties that are not found in any single material, thanks to their unique composition. For instance, fibreglass is relatively stiff, strong, and flexible, while CFRP composites are stiffer and stronger than glass fibre-reinforced materials

What are materials property charts, and what do they illustrate?

Materials property charts, also known as bubble charts or Ashby charts, present property values for different types of materials in a graphical format. They plot one property against another property on logarithmic scales, helping to show the correlation between these properties among various material families. Engineers use these charts to assess trade-offs among competing requirements when selecting materials for products

What are advanced materials?

Advanced materials are materials utilised in high-technology (high-tech) applications, including devices and products that operate using intricate and sophisticated principles. These materials are typically traditional materials with enhanced properties and newly developed, high performance materials. They can belong to all material types (eg. Metals, ceramics, polymers) and are often expensive

Name some examples of high-tech applications where advanced materials are used

Advanced materials find applications in various high-tech products and devices, such as electronic equipment (eg. cellphones, CVC players) computers, fibre-optic systems, high-energy density batteries, energy-conversion systems and aircraft.

Describe the nature of advanced materials

Advanced materials can be traditional materials when enhanced properties, achieved through advancements in manufacturing or processing techniques. Additionally, they include newly developed high-performance materials that exhibit unique characteristics suitable for high-tech applications

What are semiconductors?

Semiconductors are materials with electrical properties that lie between those of electrical conductors (eg. Metals and metal alloys) and insulators (eg. Ceramics and polymers) They are characterised by their ability to conduct electricity to some extent but are not efficient as metals in conducting, and not as resistant as insulators

How sensitive are semiconductors to impurity atoms?

Semiconductors are extremely sensitive to the presence of minute concentrations of impurity atoms. Even small amounts of impurities can significantly alter their electrical characteristics. The concentrations of impurities can be controlled over very small spatial regions

What major technological revolution have semiconductors enabled?

Semiconductors have enabled the advent of integrated circuitry, which has completely revolutionised the electronics and computer industries over the past four decades. Integrated circuits have led to the development of smaller, faster, and more powerful electronic devices and computers, significantly impacting various aspects of modern life

What are biomaterials?

Biomaterials are nonviable (nonliving) materials used to replace diseased or injured body parts in medical applications. They must function reliably and safely while interacting with living tissue. Biocompatibility is a crucial property of biomaterials, ensuring that they are compatible with body tissues and fluids without eliciting rejection or causing harmful responses

What is the significance of biomaterials in medical advancements?

Biomaterials play a vital role in extending and improving the length and quality of human lives. They are instrumental in the development of replacement implants for joint (eg. Hip and knee) and heart value replacements, vascular grafts, fracture-fixation devices, dental restorations, and the generation of new organ tissues

Name the classes of materials from which biomaterials are selected

Suitable biomaterials can be found among metal alloys, ceramics, polymers and composite materials. These materials are adapted and engineered to meet the specific biocompatibility requirements for medical application

What are smart materials?

Smart materials are new and advanced materials designed to sense changes in their environment and respond to these changes in predetermined ways. They possess traits similar to living organisms, and some smart systems include sensors and actuators for adaptive functions

Name four common types of materials used as actuators in smart systems

1. Shape-memory alloys: Metals that return to their original shape after being deformed when temperature changes
2. Piezoelectric ceramics: Materials that expand or contract in response to an applied electric field and can also generate an electric field when their dimensions are altered
3. Magnetostrictive materials: Materials responsive to magnetic fields in a manner analogous to piezoelectrics
4. Electrorheological/magnetorheological fluids: Liquids that experience significant changes in viscosity upon the application of electric and magnetic fields, respectively

What are the components of a smart material or smart system?

Smart materials or smart systems consist of two main components:
1. Sensor: Dectects input signals or changes in the environment
2. Actuator: Performs a responsive and adaptive function based on the detected changes, such as changing shape, position, mechanical characteristics, etc

Provide an example of a smart system and its application

One example of a smart system is used in helicopters to reduce aerodynamic cockpit noise cause by rotating rotor blades. Piezoelectric sensors inserted into the blades monitor blade stresses and deformations. These sensors feed feedback signals into a computer-controlled adaptive device, which generates noise-canceling anti noise to mitigate the noise

What are nanomaterials?

Nanomaterials are a class of materials characterised by their size, with dimensions on the orders of a a nanometer (10^-9 m), typically less than 100 nanometers. They can be metals, ceramics, polymers, or composites, and their properties may drastically differ from their macroscopic counterparts due to their size

What is the bottom-up approach in nanotechnology?

The bottom-up approach in nanotechnology involves designing and building new structures from atomic-level constituents, arranging atoms one by one. This approach enables the development of unique properties that are not achievable through traditional methods, offering opportunities in mechanical, electrical, magnetic and other areas

Name some unique properties exhibited by nanomaterials

Nanomaterials may exhibit unique properties such as opacity to transparency transformation, materials changing from a solid to liquid state, combustible behaviour in usually stable substances, and insulators becoming conductors. Some effects are quantum mechanical in origin, while others relate to surface phenomena due to higher proportion of atoms on surface sites in nanoscale particles

What are some industrial applications of nanomaterials

Catalytic converters for automobiles, nanocarbons like fullerenes, carbon nanotubes, and graphene, carbon black particles used as tire reinforcement, nanocomposities, magnetic nano size grains for hard disk drives and magnetic particles storing data on magnetic tapes

What are some concerns regarding nanomaterials safety?

Nanomaterials have high chemical reactivities due to their exceedingly large surface area to volume ratios. Safety concerns include the potential for nanomaterials to be absorbed into the body through the skin, lungs and digestive tract, leading to potential health risks such as DNA damage or promotion of lung cancer

What challenges are found in Renewable Energy?

- Demand for cost effective materials in solar cells and batteries
- Need for efficient solar cell materials and high-energy-density batteries

What challenges are found in transportation?

- Focus on materials to reduce vehicle weight and withstand higher engine temperatures
- Development of high-strength, low-density structural materials for transportation vehicles

What challenges are found in Hydrogen Fuel Cells?

- Advancements needed for more efficient fuel cells and better hydrogen production catalysts
- Hydrogen fuel cells as a non polluting energy-conversion technology

What challenges are found in Nuclear Energy?

- Research on materials for nuclear fuels, containment structures, and radioactive waste disposal
- Potential of nuclear energy as a sustainable power source

What challenges are found in Pollution Control?

- Role of materials in controlling air and water pollution
- Need for improved processing methods with reduced environmental impact

What challenges are found in Sustainable Resources?

- Depletion of non renewable resources, promoting research into alternative materials
- Focus on sustainable materials in increased recycling efforts

What challenges are found in Life Cycle Assessments?

- Consideration of materials entire life cycle, from production to disposal
- Importance of economic and environmental impacts in materials selection

Atomic Structure definition and importance

Definition: Arrangement of atoms in solid materials, which influences their properties
Importance: Understanding atomic structure helps explain various material properties

Electron Configuration definition and relevance

Definition: Distribution of electrons in the electron shells and sub shells of atoms
Relevance: Configurations determine atom's chemical properties and bonding behaviour

Periodic Table definition and significance

Definition: Tabular arrangement of elements based on their atomic number and electron configurations
Significance: Organises elements and reveals trends in their properties

Interatomic Bonds definition, types of bonds and importance

Definition: Forces that hold atoms together in a solid material
Types of Bonds: Primary (ionic, covalent, metallic) and secondary (hydrogen, van der waals) bonds
Importance: Bond types influence the material's properties, such as strength and conductivity

Subatomic Particles

- Atoms consist of a small nucleus composed of protons and neutrons, surrounded by moving electrons
- Protons and electrons are electrically charged, with magnitudes of 1.602 x 10^-19 C
- Neautrons are electrically neutral
- Masses: Protons and neutrons have a mass of approximately 1.67 x 10^-27 kg, while electrons are much lighter with a mass of 9.11 x 10^-31kg

Atomic Number (Z)

- The number of protons in the nucleus, uniquely defining each chemical element
- For an electrically neautral atom, the atomic number also equals the number of electrons
- Ranges from 1 for hydrogen to 92 for uranium

Atomic Mass (A) and Isotopes

- Atomic mass (A) is the sum of protons and neutrons in the nucleus
- Isotopes are atoms atoms of the same element with different numbers of neutrons, leading to different atomic masses
- Atomic weight is the weighted average of the atomic masses of naturally occurring isotopes

Atomic Mass Unit (AMU)

- 1 amu is defined as 1/12 of the atomic mass or carbon-12 (12c), which has A = 12.00000
- Protons and neautrons have slightly greater masses than 1 amu

Molar Mass

- Atomic weight (in amu/atom or molecule) and molar mass (in g/mol) are related by the equation: 1 amu/atom (or molecules) =1 g/mol
- The molar mass represents the mass of one mole of a substance, containing Avogradro's number (6.022 x 10^23) of atoms or molecules

What are the subatomic particles that compose an atom?

Atoms are composed of a small nucleus containing protons and neutrons, surrounded by moving electrons

What are the electric charges of protons and electrons?

Protons have a positive charge and electrons have a negative charge

What is the mass of protons and neutrons compared to electrons?

Protons and neutrons have a mass of approximately 1.67 x 10^-27kg, which is much larger than the mass of electrons (9.11 x 10^-31kg)

What does the atomic number Z represent?

The atomic number (Z) represents the number of protons in the nucleus and uniquely defines each chemical element

What is the atomic mass (A) of an atom?

The atomic mass (A) is the sum of protons and neutrons in the nucleus of an atom

What are isotopes?

Isotopes are atoms of the same element with different numbers of neutrons, leading to different atomic masses

How is the atomic weight calculated for an element?

The atomic weight is the weighted average of the atomic masses of naturally occurring isotopes

What is an atomic mass unit (amu) defined as?

1 amu is defined as 1/12 of the atomic mass of carbon-12 (12C)

How are atomic weight (amu/atom or molecule) and molar mass (g/mol) related?

1 amu/atom (or molecule) is equal to 1g/mol

What is the unit of atomic weight predominantly used?

The molar mass (grams per mole)

How do you compute the average atomic weight (AM) of an element with multiple isotopes?

The average atomic weight (AM) of an element is calculated by summing the fraction-of-occurrence (fi) of each isotope multiplied by its atomic weight (Ai)

AM = ∑ ( fi * Ai)

What was Bohr's model?

Electrons travel around the nucleus in well defined paths called the orbit, in which different orbits contain electrons with different amounts of energy.

What was Bohr's theory?

Electron energies are quantised, meaning they can only have specific energy values. When electrons change energy levels, they make quantum jumps to higher or lower energy states

What limitations were found in the Bohr atomic model and how was it improved?

It had limitations in explaining several phenomena involving electrons. It was improved with the wave-mechanical model, which considers the electron to exhibit both wavelike and particle-like characteristics.

How does the wave-mechanical model differ from the Bohr atomic model?

The wave-mechanical model treats electrons as having both wave and particle properties. It describes an electron's position as a probability distribution or electron cloud, rather than fixed orbits as in the Bohr model. This allows for a more accurate representation of electron behaviour in atoms and crystalline solids

How many quantum numbers are used to characterise every electron in an atom, and what do they specify?

Four quantum numbers are used to characterise each electron in an atom. Three of these numbers specify size, shape and spatial orientation of an electron's probability density or orbital

What does the principle quantum number (n) represent and what values can it take?

N specifies the shells in an atoms. It can take integral values beginning with unity (n = 1) and it is associated with the size of an electron's orbital or its average distance from the nucleus

How are subshells designated, and what do they depend on?

By lowercase letters s, p, d and f. They depend on the second (azimuthal) quantum number (l) which takes integer values from 0 to (n - 1).

Describe the shapes of s and p orbitals

S orbitals are spherical and cantered on the nucleus. P orbital have a nodal surface in the shape of a dumbbell with three perpendicular axes labeled px, py and pz

How many electron

The number of electron orbitals for each subshell is determined by the third (magnetic) quantum number (ml). For a given value of l, ml can take on integer values between -1 and +1, including 0. eg. S subshell has one orbital (ml = 0) p subshell has three (ml = 1,0,+1), d subshell has five and f subshell has seven

What is the fourth quantum number and what are the two possible values?

Spin quantum number (ms). It is associated with the spin movement of each electron and can have two values +1/2 (for spin up) and -1/2 (for spin down)

What is the Pauli exclusion principe and how does it affect the filling of electron states?

Each electron state can hold a maximum of two electrons with opposite spins and determines how electrons are filled in s, p, d, f subshells with 2, 6, 10 and 14 electrons

What is the ground state of an atom and how do electrons occupy energy states in this state?

When all electrons occupy the lowest possible energy states in the electron shells and subshells, with two electrons (opposite spins) per state. The ground state represents the most stable configuration for an atom

What does the electron configuration of an atom represent and how it is written in conventional notation?

Represents the manner in which electron states are occupied. The number of electrons in each subshell is indicated by a superscript after the shell-subshell designation eg. Sodium 1s2, 2s2, 2p6, 3s1

What are valence electrons and why are they important?

Valence electrons are the electrons in the outermost energy level. They tell us the element's reactivity. They determine many of the physical and chemical properties of solids

What are stable electron configurations and which elements have them?

Stable electron configurations refer to states where the outermost or valence electron shell is completely filled. Usually s and p states contain eight electrons, except helium, which has two 1s electrons. Noble gases like neon, argon, krypton and helium have stable electron configurations and are chemically unreactive.

How are elements arranged on the periodic table?

Increasing atomic number

What are horizontal rows in the periodic table called?

Periods

What role do vertical columns or groups in the periodic table play?

Elements in the same vertical columns or group have similar valence electron structures as well as similar chemical and physical properties. Properties change gradually moving horizontally across each period and vertically down each column