Material Science: Introduction

• Module 1 is an introduction to material science
• The PowerPoint presentation is by Engr. Rosemary V. Saavedra

About the Instructor

• Engr. Rosemary V. Saavedra was born in November 1961.
• She is a graduate of Bachelor of Science in Civil Engineering (BSCE) from Luzonian University Foundation Batch 1984.

Reference Book

• The reference book for the course is the 8th Edition of "Material Science and Engineering."
• The book is written by William D. Callister and David G. Rethwisch.

Module 1 Objectives

• List six classifications of material properties that determine their applicability
• Cite the four components involved in the design, production, and utilization of materials and describe their interrelationships

Materials Engineering

• Materials engineering is the discipline of designing or engineering the structure of a material.
• The goal is to produce a predetermined set of properties based on established structure-property correlations.

Materials Science

• Materials science is the investigation of the relationships that exist between the structures and properties of materials.

Importance of Material Science and Engineering

• Professional engineers must select materials that fit design requirements:
  • Economic demands
  • Aesthetic demands
  • Strength and durability
• This enables the engineer to:
  • Select a material based on cost and performance
  • Understand material limits and property changes during use
  • Create new materials with desirable properties
  • Use materials for different applications

Classification of Materials

• Materials are classified based on criteria like crystal structure, properties, or use.
• Main classes of engineering materials:
  • Metals
  • Ceramics
  • Polymers
  • Composites
  • Semiconductors
  • Biomaterials

Metal

• Metals have high thermal and electrical conductivity.
• They are strong yet deformable under applied mechanical loads.
• Metals are opaque to light (shiny if polished).
• Valence electrons are detached from atoms and spread in an electron sea, gluing ions together via metallic bonds.
• Pure metals are often inadequate for structural applications, leading to the use of alloys.
• Alloys are metal mixed with another metal to improve desired qualities
• Examples: aluminum, steel, brass, gold

Ceramics

• Ceramics consist of inorganic compounds.
• They are made of oxides, carbides, nitrides, or silicates of metals.
• Ceramics are partly crystalline and partly amorphous.
• Atoms in ceramic materials behave like positive or negative ions
• These are bound by strong forces
• Ceramics have high strength under compression and low ductility.
• They are usually insulators of heat and electricity.
• Examples include glass, porcelain, and many minerals.

Polymers

• Thermoplastics (nylon, polyethylene, polyvinyl chloride, rubber) consist of molecules with covalent bonding within each molecule.
• Thermosets (epoxy, phenolics) consist of a network of covalent bonds.
• Polymers are based on H, C, and other non-metallic elements.
• Polymers are amorphous, except for a minority of thermoplastics.
• Polymers are typically electrical and thermal insulators due to their bonding.
• Conducting polymers can be obtained by doping or using conducting fillers in polymer-matrix composites.
• They decompose at moderate temperatures (100 – 400 C).
• These materials typically have low densities and may be extremely flexible.

Composite Material

• Composite materials are multiphase and created by combining different materials artificially.
• The goal is to achieve properties that individual components cannot attain on their own.
• An example is a lightweight brake disc with SiC particles in Alalloy matrix.
• Reinforced cement concrete is a structural composite of cement (matrix/binder from hydration), sand (fine aggregate), gravel (coarse aggregate), and thick steel fibers.

Advance Materials

• Advanced materials are used in high-tech applications and devices that operate with relatively intricate and sophisticated principles.
• Examples include:
  • Electronic equipment (camcorders, CD/DVD players)
  • Computers
  • Fiber-optic systems
  • Spacecraft
  • Aircraft
  • Military rocketry

Semiconductors

• Semiconductors have electrical properties intermediate between conductors and insulators.
• The electrical characteristics are sensitive to minute impurity concentrations, controllable over very small spatial regions.
• Semiconductors enabled integrated circuitry, revolutionizing the electronics and computer industries.

Biomaterials

• Biomaterials are for components implanted into the human body.
• They replace diseased or damaged body parts.
• These materials must not produce toxic substances.
• They must be compatible with body tissues to avoid adverse biological reactions.
• Metals, ceramics, polymers, composites, and semiconductors can be used as biomaterials.

Smart Material

• Smart (or intelligent) materials are state-of-the-art materials that significantly influence technologies.
• Smart materials sense changes in their environment.
• They respond in predetermined manners like living organisms.
• This "smart" concept extends to sophisticated systems with smart and traditional materials.

Nanomaterials

• Nanomaterials, a novel material class, exhibit fascinating properties.
• They hold tremendous technological promise.
• Nanomaterials can be metals, ceramics, polymers, or composites.
• Unlike other materials, they are distinguished by size rather than chemistry.
• The nano-prefix denotes dimensions on the order of a nanometer (10–9 m), less than 100 nanometers (approximately 500 atom diameters).