Engineering Materials: An Introduction

• This lecture introduces the fundamental concepts of engineering materials.
• The course studies material science and engineering.

Instructor Information

• The instructor is Dr. Manar Almazrouei.
• Contact Dr. Almazrouei via email at [email protected]
• Office hours are by appointment.
• The office is located in F1 Building, Room 1014.

Assessment Structure

• The midterm exam is worth 25% of the final grade.
• The final exam is worth 40% of the final grade.
• Quizzes account for 15% of the final grade.
• Lab reports and assignments make up 10% of the final grade.
• The project contributes 10% to the final grade.

Class Schedule

• Section 01 meets on Mondays from 8:00-9:50 AM in F1-134.
• Section 03 meets on Mondays from 6:00-7:50 PM in F3-040.

Required Textbook

• The required textbook is "Materials Science and Engineering: An Introduction" by Callister Jr, William D., and David G. Rethwisch, published by John Wiley & Sons.

Course Objectives

• Students will study basic concepts and fundamentals of material science and engineering

Covered Topics

• The course covers atomic structure (arrangements, unit cells).
• Types of engineering materials: metallic alloys, polymers, ceramics, composites, and nanocomposites.
• Material testing and characterization techniques.
• Mechanical and electrical properties, material processing, and in-service behavior.
• In-service behavior includes corrosion, deformation, as well as material and process selection.

Learning Outcomes

• Students will be able to explain concepts of crystalline and non-crystalline material structures and their defects.
• Students will be able to use Fick’s first and second laws of diffusion in metals.
• Students will be able to illustrate corrosion and electrical properties of metals and semiconductors.
• Students will be able to practice material testing, produce technical reports, and identify issues related to engineering materials.

Material Ages

• Stone Age: Before 3500 BC
• Bronze Age: 3500-1000 BC
• Iron Age: 1000 BC-1620 AD
• Steel Age: 1620-1960
• Silicon Age: 1960-present

Key Points

• Materials have shaped human civilization.
• Technological advancements are often linked to material innovations.

What is Materials Science and Engineering

• Materials Science studies relationships between structures and properties of materials.
• Materials Engineering designs or engineers material structures for specific properties.

Why Study Materials Science and Engineering

• To design and create better products.
• To select materials for applications, predict material behavior, and improve material properties.
• To solve material-related failures.

Liberty Ship Failures Case Study

• During World War II, mass-produced Liberty ships experienced structural failures in 1943.
• Key issues: ductile-to-brittle transition in cold temperatures, stress concentration at hatch corners, and weld defects.
• Lessons learned include the importance of material selection, design improvements, welding practices, and fracture mechanics.

Structure Overview

• Structure refers to the arrangement of internal components.
• Structural elements include subatomic particles, atoms, nanostructures (less than 100 nm), microstructures (100 nm to mm), and macrostructures (mm to m).

Material Property Types

• Basic properties are traits responding to a stimulus.
• Physical properties: mechanical, electrical, and thermal.
• Additional properties: magnetic, optical, and deteriorative.
• Mechanical properties respond to applied forces.
• Electrical properties respond to electric fields, like conductivity and dielectric constant
• Thermal properties respond to temperature changes, such as thermal expansion and heat capacity.
• Magnetic properties respond to magnetic fields.
• Optical properties respond to electromagnetic radiation.
• Deteriorative properties describe reaction to environmental factors, such as corrosion resistance.

Electrical Resistivity of Copper

• Adding impurity atoms increases resistivity.
• Deforming copper increases resistivity.

Thermal Properties

• Thermal conductivity of copper decreases when zinc is added.
• Space Shuttle tiles use silica fiber insulation for low heat conduction due to highly porous materials

Magnetic Properties

• Magnetic storage records using a magnetized medium and write head.
• Magnetic Permeability: Adding 3% atomic Si to Fe improves its recording medium capabilities.

Optical Properties of Aluminum Oxide

• Crystal structure affects transmittance.
• A single crystal is transparent (high degree of perfection, allows all light to pass through).
• Polycrystalline is translucent (multiple small crystals, crystal boundaries scatter light).
• Porous polycrystalline is opaque (small crystals with pores, pores block light).
• Same material (Al2O3), different processing leads to different properties.

Deteriorative Properties

• Stress and saltwater exposure causes cracks.
• Heat treatment slows crack speed in salt water.

Structure, Processing, Properties, and Performance

• Four key components: processing, structure, properties, and performance.
• These components are interrelated for design, production, and utilization
• Structure depends on processing methods, and performance is a function of properties.
• Properties depend on structure, with hardness vs structure of steel as an example.
• Processing can change structure, with structure vs cooling rate of steel as an example.

Material Classification

• Basic categories: metals, ceramics, and polymers.
• Advanced materials: composites and materials like semiconductors, biomaterials, smart materials, and nanomaterials.

Metals Key Properties

• Metals are composed of metallic elements (e.g., Fe, Al, Cu, Ti).
• May contain small amounts of non-metals (C, N, O).
• Orderly atomic arrangement and high density.
• Metals are relatively stiff and strong.
• Metals are ductile, resistant to fracture, and have excellent electrical conductivity.
• Common examples: Iron/Steel, Aluminum, Copper, Titanium.

Mechanical Properties of Metals

• Metals exhibit high density and stiffness.
• Also exhibit high strength and fracture resistance.

Ceramics Key Properties

• Ceramics are compounds of metallic and nonmetallic elements (oxides, nitrides, carbides).
• They Includes traditional materials (clay, cement, glass).
• Stiff, strong, and typically very hard.
• Brittle (low ductility, susceptible to fracture).
• Insulators of heat and electricity.
• Resistant to high temperatures and harsh environments.
• Some oxides exhibit magnetic behavior (e.g., Fe3O4 ).
• Can be transparent, translucent, or opaque.
• Common ceramics: Alumina (Al2O3), Silica (SiO2), Silicon Carbide (SiC), and Silicon Nitride (Si3N4).

Polymers Key Properties

• Polymers are organic compounds based on carbon, hydrogen, and nonmetallic elements (O, N, Si).
• Large molecular structures that are chain-like with a carbon atom backbone
• Low densities, lower stiffness and strengths, nonmagnetic, and low electrical conductivity.
• In comparison to metals and ceramics, polymers are easily formed into complex shapes (ductile and pliable).
• Chemically inert and non-reactive in most environments.
• Polymers often soften or decomposes at modest temperatures.
• Common polymers include Polyethylene (PE), Nylon, Poly(vinyl chloride) (PVC), Polycarbonate (PC), Polystyrene (PS), and Silicone rubber.

Composites Key features

• Composites are composed of two or more materials (metals, ceramics, polymers) to combine their properties.
• Common composites are Fiberglass (glass fibers embedded in a polymer matrix) and CFRP (carbon fiber-reinforced polymer)
• CFRP is stronger, stiffer, and more expensive than fiberglass.
• Composites are used for high strength, stiffness, and lightweight applications.
• Applications of CFRP include use in aerospace, sporting equipment, and automotive parts.

Advanced Materials Key Characteristics

• Advanced materials are for high-technology applications.
• Enhanced traditional or newly developed high-performance materials.
• Can be metals, ceramics, or polymers and are typically expensive.
• Include semiconductors, biomaterials, smart materials, and nanoengineered materials.
• Applications include electronic equipment, computers, spacecraft, military rocketry, lasers, and LCDs.

Semiconductors Key characteristics

• Semiconductors have properties between those of conductors and insulators,
• Semiconductors are sensitive to impurity concentrations.
• Enabled integrated circuits and revolutionized electronics
• Examples include Silicon (Si), Germanium (Ge), Gallium Arsenide (GaAs), Silicon Carbide (SiC), and Indium Phosphide (InP).

Biomaterials definition

• Biomaterials are materials used in implanted components.
• Intended to replace diseased or damaged body parts.
• They must not produce toxic substances, must be compatible with body tissues and not cause adverse biological reactions.
• Metals, ceramics, polymers, composites, and semiconductors may all be used as biomaterials.
• Biomaterials have evolved from simple replacements to advanced, engineered tissues and organs.

Smart Materials

• Smart Materials sense and respond to environmental changes, mimicking traits of living organisms.
• They possess sensors (detect input signals) and actuators (perform responsive functions).
• Actuators include shape-memory alloys, piezoelectric ceramics, and magnetostrictive materials.
• Electro/magnetorheological fluids change viscosity with electric/magnetic fields.

Nanomaterials definition

• Nanomaterials are materials with structural entities on the order of 1-100 nanometers.
• Can be metals, ceramics, polymers, or composites
• They Are distinguished by size, not by chemistry
• Have unique properties compared to their bulk counterparts due to their small size.

Approaches to Nanomaterials

• Top-down approach: breaks down larger materials with techniques like mechanical milling, etching, and laser ablation.
• Bottom-up approach: builds structures atom-by-atom with techniques like supercritical fluid synthesis, sol-gel process, and chemical vapor deposition.

Modern Materials' Needs

• Energy: nuclear (fuels, containment), transportation (lightweight), solar (efficient), hydrogen (catalysts).
• Environmental: pollution control, reduced degradation, ecological impact.
• Resource Management: alternatives for nonrenewable resources, new reserves, comparable properties, and increased recycling.
• Manufacturing: sophisticated materials, improved methods, and consideration of the cradle-to-grave life cycle.

Key Takeaways:

• The relation between properties, structure, and processing.
• Learn the three classifications of materials are metals, ceramics, and polymers
• Study the properties such as mechanical, electrical, thermal, magnetic, optical, and deteriorative.
• Recognize new design opportunities offered by materials selection.