Intro to Material Science and Engineering

• These are study notes for an introductory lecture on Material Science and Engineering.

Introduction

• Titanic was considered unsinkable due to its engineering.
• The Hindenburg airship used hydrogen for buoyancy.
• The outer skin was made of cotton coated with iron oxide (Fe₂O₃) and aluminum powder making it highly susceptible to ignition.
• Samsung Galaxy Note 7 explosions were due to design flaws in the lithium-ion battery separator, which was too fragile.

Material Science

• Involves studying the relationships between the structures and properties of materials.
• Examines how the atomic and molecular structure affects electrical, thermal, & mechanical properties.

Material Engineering

• Involves designing and engineering the structure of a material to produce specific properties.
• Focuses on modifying, enhancing, or creating new materials for better performance in electronic components.

Components of Material Science and Engineering (MSE)

• Structure refers to the arrangement of internal components at different levels.

• Subatomic level involves electrons, protons, and neutrons.

• Atomic level involves elements from the periodic table and their atomic structure.

• Microscopic level involves groups of atoms bonded together.

• Macroscopic level involves structures visible to the naked eye.

• Property refers to a material trait in terms of its response to a specific stimulus.

• Mechanical properties involve deformation under load or force.

• Electrical properties include conductivity and dielectric constant.

• Thermal properties include heat capacity.

• Magnetic properties involve response to a magnetic field.

• Optical properties involve response to electromagnetic waves/light.

• Deteriorative properties involve chemical reactivity.

Example Materials

• Silicon (Si):

• Structure: Diamond cubic crystal, semiconductor with a 1.12 eV band gap.

• Properties: High melting point (1414°C), brittle, excellent thermal and electrical conductivity.

• Performance: Used in microchips, solar panels, optical fibers, and MEMS sensors.

• Processing: Extracted from quartz, purified via the Czochralski process and doped for conductivity control.

• Characterization: XRD (crystal structure), SEM (surface analysis), Four-Point Probe (resistivity), and Raman Spectroscopy (stress measurement).

• Cotton (Natural Fiber):

• Structure: Cellulose (C₆H₁₀O₅)n with crystalline and amorphous arrangement, forming a fibrous structure.

• Properties: Soft, lightweight, breathable, high moisture absorption, biodegradable, but prone to wrinkling/shrinking.

• Performance: Used in textiles, medical bandages, paper, and insulation (comfort, durability, biodegradability).

• Processing: Harvested, cleaned, spun into yarn, woven into fabric, and chemically treated (bleaching, dyeing).

• Characterization: SEM (fiber structure), FTIR (chemical composition), TGA (thermal stability), moisture absorption, and tensile testing.

Why Study Material Science and Engineering?

• Facilitates material selection for various applications.
• Enables the fabrication of new materials with enhanced properties.
• Aids in the investigation and understanding of material behavior.

Solid Materials

• Metals:

• Compounds containing one or more metallic elements.

• Strong, stiff, ductile, resistant to fracture, and excellent conductors.

• Examples: Metal Alloys.

• Ceramics:

• Compounds between metallic and nonmetallic elements.

• Strong, stiff, hard, and insulative to heat and electricity but prone to fracture.

• Examples: Clay and Porcelain.

• Polymers:

• Organic compounds based on nonmetallic elements.

• Not stiff or strong, but ductile and pliable, allowing easy deformation.

• Examples: Plastic and Rubber.

• Composites:

• Composed of two or more individual materials, combining the best characteristics of each.

• Examples: Cement and Fiber Glass.

Advanced Materials

• Semiconductors:

• Electrical properties are between conductors and insulators.

• Extremely sensitive to impurities.

• Used in Integrated Circuits.

• Biomaterials:

• Implanted components that replace or repair damaged body parts.

• Must be non-toxic and compatible with body tissues.

• Used in Artificial Parts.

• Smart Materials:

• Intelligent materials that can sense changes in their environment.

• Used in Sensors.

• Nanomaterials:

• Future technologies utilizing structural features on the nanometer scale.

Research Task

• Analyze different materials used for specific items to understand their properties and applications.
• Tempered Glass, Soda-Lime Glass, Aluminosilicate Glass, Sapphire Glass, Ion-Exchange Processed Glass
• Hybrid Glass-Polymer Composite