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MATERIAL ENGINEERING - Coggle Diagram
MATERIAL ENGINEERING
CHAPTER 1 INTRODUCTION TO MATERIAL
FUNDAMENTALS & HISTORICAL EVOLUTION
Engineering Materials: Materials used to produce technical products engineered to exhibit specific desired properties (mechanical, optical, thermal, electrical, magnetic, deteriorative).
Evolutionary Timeline of Materials:
Stone Age: Naturally occurring materials (stone, wood, clay).
Bronze & Iron Age: Fire and melting technologies to produce superior properties (copper alloys, iron, steel).
Industrial Revolution: Iron, steel, steam engines, machine tools, structural innovations.
Electric Age (Silicon Age): Past 100 years — semiconductors, microprocessors, electronic systems.
Designed Materials Age: Advanced composites, surface treatments, artificial layered structures.
Nano & Smart Material Age / IR 4.0: Nanotechnology, bio-hybrids, smart responsive structures.
Definition of Materials: Substances from which something is composed or made. Human progress and civilization are closely tied to material development.
PRIMARY SOLID MATERIAL CLASSIFICATIONS
Metals & Alloys
Structure: Metallic bonding; inorganic; crystalline structure; non-localized free valence electrons.
Properties: High strength, high elastic modulus, stiff, dense, ductile (large deformation without fracture), high thermal & electrical conductivity.
Applications: Phone structural frames (Titanium), power transmission gears, aerospace structures, IC engines.
2. Ceramics
Structure: Ionic & covalent bonding; inorganic compounds of metallic + non-metallic elements (oxides, nitrides, carbides); crystalline, non-crystalline (glasses), or mixed.
Properties: High melting points, extreme hardness, high compressive strength, chemical stability/corrosion resistance, brittle (lacks ductility), poor thermal/electrical conductors.
Applications: Ultra-thin bendable glass screens (Samsung Galaxy Z Flip), laboratory glassware, dental implants/crowns, heat shields.
3. Polymers
Structure: Covalent backbone + secondary bonding; organic long-chain molecular networks (C, H, O, N, Si); mostly non-crystalline or semi-crystalline.
Sub-categories: Thermoplastics, Thermosets, Elastomers.
Properties: Very low density, lightweight, flexible, low melting point/thermal resistance, poor electrical conductors.
Applications: Equipment housings, bio-based automotive components, insulation, packaging.
4. Composites
Structure: Multi-phase combination of 2+ distinct materials (Matrix Phase + Reinforcing Phase).
Sub-categories: Metal Matrix (MMC), Ceramic Matrix (CMC), Polymer Matrix (PMC).
Properties: Best properties combined; high strength-to-weight ratio; high stiffness; tailored multi-directional orientation.
Applications: Aircraft wings & fuselages (Airbus A350: 53% composites, Boeing 787: 50% CFRP), sports equipment.
ADVANCED & EMERGING HIGH-TECH MATERIALS
Semiconductors: Intermediate electrical conductivity between conductors and insulators. Properties are highly sensitive to minute concentrations of impurity atoms (doping) in precise spatial regions. Used in integrated circuits, microprocessors, and IC packaging (2D $\rightarrow$ 2.5D $\rightarrow$ 3D integration).
Biomaterials: Implanted into the human body to replace/repair damaged or diseased organs/tissues. Requires strict biocompatibility (non-toxic, compatible with host tissue). Examples include CoCrMo/Titanium hip joint implants, Platinum cranioplasty mesh, Nitinol cardiovascular stents, 3D-printed bone scaffolding, and PLA hydrogels.
Smart Materials: Ability to sense environmental changes and automatically respond in a predetermined manner. Incorporates Sensors (input detection) and Actuators (adaptive responsive action). Key types include Shape Memory Alloys (SMA / Muscle Wire), Piezoelectric Ceramics, Magnetostrictive materials, and Ferrofluids.
Nano-Engineered Materials: Structural features constrained to dimensions $< 100\text{ nm}$. Examples include Carbon Nanotubes (CNTs), targeted drug delivery pumps/systems (DDS), and nanomedical micro-devices.
REAL-WORLD ENGINEERING CASE STUDIES
Failure Analysis: RMS Titanic Sinking (1912)
Root Cause: Metallurgical failure due to incomplete understanding of low-temperature material behavior.
Mechanism: Plain carbon steel hull plates exhibited a high Ductile-to-Brittle Transition Temperature (DBTT).
Operating Environment: Seawater temperature was $-2^\circ\text{C}$, causing steel to undergo brittle fracture upon iceberg impact rather than deforming plastically.
2. Mobile Phone Engineering & Smart Devices
Foldable Screens: Ultra-Thin Glass (UTG) treated with chemical baths and thermal tempering to allow flexibility while maintaining optical clarity and scratch resistance.
Chassis / Frame: Titanium preferred over Aluminum due to equivalent strength to steel at 50% lower mass, superior corrosion resistance, and high temperature tolerance.
3. Thermal Management: Electronic Heat Sinks
Selection Parameters: Thermal Conductivity ($W/m\cdot K$), Density ($g/cm^3$), Manufacturing Cost, Surface Finish, Max Section Size.
Material Profiles:
Aluminum: $235\text{ W/m}\cdot\text{K}$, $2.70\text{ g/cm}^3$ (Low cost, extruded/die-cast)
Copper: $400\text{ W/m}\cdot\text{K}$, $8.96\text{ g/cm}^3$ (High thermal performance, heavier, skived/machined)
Graphite Composite: $370\text{ W/m}\cdot\text{K}$, $1.89\text{ g/cm}^3$ (High conductivity, very low density)
CarbAl™ (Nanotech): $425\text{ W/m}\cdot\text{K}$, $1.75\text{ g/cm}^3$ (Ultra-high performance nanocomposite)
4. Sustainable Automotive Design & E-Waste Lifecycle
Biomass / Bio-Plastics: Substituting petroleum plastics with renewable carbon (PLA, soy foams, natural fibers like kenaf, hemp, sisal, abaca, dandelion rubber) in car interiors, tires, and under-hood components.
E-Waste Management: Multi-step recycling flow for end-of-life electronics (Collection $\rightarrow$ Dismantling $\rightarrow$ Component Sorting $\rightarrow$ Shredding $\rightarrow$ Milling/Sieving to particle sizes $\le 150\,\mu\text{m}$).
CHAPTER 2 BONDING & PROPERTIES
THE PERIODIC TABLE
Column: Similar valence sturcture
Electropositive elements
Readily give up electrons to become + ions.
Electronegative elements
Readily acquire electrons to become - ions
Ranges from 0.7 to 4.0
Large values: tendency to acquire electrons
Increase from left to right
ATOMIC MODELS
ATOMIC WEIGHT
The weighted average of atomic masses
of an atom’s naturally occurring isotopes.
TWO TYPES ATOMIC MODELS 1.Bohr Atomic Model 2.Wave -mechanical model
Bohr Atomic Model
Orbital Paths: Assumes electrons revolve around the atomic nucleus in discrete orbitals, making the position of an electron relatively well-defined
.
Quantized Energy States: Electron energies are quantized into specific allowed energy levels, with electrons naturally occupying the lowest available energy state
.
Energy Transitions: Energy changes occur through quantum jumps between allowed states—absorbing energy when transitioning to a higher level and emitting energy when dropping to a lower level
Wave-Mechanical Model
Wave-Mechanical Model
Dual Nature: Views the electron as having both wave-like and particle-like characteristics, rather than existing as a classical particle constrained to a discrete orbital path. Electron Cloud & Probability: The location of an electron is described by a probability distribution within an electron cloud
BONDING FORCES & ENERGIES
Interatomic Forces
Attractive Force
Pulls the atoms closer together
Positive force
Repulsive Force
short-range force arising as the outer electron shells overlap, causing repulsion between the atomic nuclei and electron clouds
Negative force
Net Force
The overall force acting on the atom pair
Sum of attractive force and repulsive force
Interatomic Parameters
Equilibrium Interatomic Distance (or lattice constant)
attractive force = repulsive force
Minimum potential energy
Maximum stability
Binding/Bonding Energy
Energy per atom required to dissociate from the solid
Measure of the strength of the solid
Potential Energy Relationships
Integration of interatomic force
Properties from bonding
Melting Temperature, Tm
Increase when bonding energy increase
Coefficient of Thermal Expansion
Increase when bonding energy decrease
Equal to change of length/(original length*change of temperature)
INTERATOMIC BOND
Primary Bonding
Ionic Bond
Metal and Non-metal
Large difference in electronegativity
Valence electrons are transferred from electropositive atoms to electronegative atoms, forming positive cations and negative anions
Held together by electrostatic Coulombic attraction
Non-directional
high melting temperatures, high hardness, brittleness, and thermal/electrical insulation
Ceramics
Covelent Bond
Non-metal molecules
Sharing of valence electrons to attain stable electron configurations
Highly directional
Bond energies and melting temperatures span a wide range
Structure
Simple molecular structure
Giant molecular structure
Graphite
Conductor
Diamond
Hard
High melting point
Semiconductors, ceramics, polymer chains
Metallic Bond
Metal
Valence electrons (1, 2, or 3 per atom) are delocalized and shared across the entire solid, forming a "sea of electrons" or "electron cloud" surrounding positive ion
Non-directional
Group IA and IIA elements
Highly conductive, ductile,
Binding energy & melting temp (wide range)
Secondary bonding
van der Waals bonds
Binding energy (typical) in the order of 10 kJ/mol (0.1 eV/atom)
Exist between virtually all atoms or molecules.
The presence of any of the 3 primary bonding types may obscure it.
This force arises from atomic or molecular dipoles to electric dipoles.
Separation of positive and negative portions of an atom or molecule
Coulombic attraction between +ve end of one dipole and –ve end dipole.
Fluctuating dipoles
Momentary, asymmetric electron distributions in electrically symmetric atoms or nonpolar molecules
Permanent dipoles-molecule induced
Polar molecules with inherent charge asymmetry
Hydrogen bond
Occurs when Hydrogen covalently bonds to highly electronegative atoms (O, N, F)