MET Module 5-8 Materials Science PDF

**MODULE 5** ------------ **CORROSION** - - **Forms of Corrosion** 1. - - - - - - 2. - - - - - 3. - - - - - 4. - - - - - 5. - - - - - 6. - - - - 7. - - - - 8. - - - - **Hydrog...

**MODULE 5** ------------ **CORROSION** - - **Forms of Corrosion** 1. - - - - - - 2. - - - - - 3. - - - - - 4. - - - - - 5. - - - - - 6. - - - - 7. - - - - 8. - - - - **Hydrogen Embrittlement** - - - - - **MODULE 6** ------------ **FERROUS AND NONFERROUS METALS** **Metal** A metal is typically hard, opaque, shiny, and has good electrical and thermal conductivity. Metals are generally malleable (can be hammered or pressed without breaking), fusible (meltable), and ductile (can be drawn into thin wires). Astrophysicists define \"metal\" broadly to include all elements except hydrogen and helium. **Types of Metal Alloys** Metal alloys are grouped into two classes: 1. 2. **Ferrous Alloys** These alloys, with iron as the prime constituent, are used extensively in engineering due to their abundance, economical production techniques, and versatility. However, they are prone to corrosion. Steels - - - - Stainless Steels Resistant to corrosion due to chromium content (\>11%). Types include: 1. 2. 3. Cast Irons Characterized by \>2.14% carbon, commonly between 3-4.5%. Types include: - - - - - **Non-Ferrous Alloys** Metals without iron, typically resistant to corrosion and lightweight. 1. - 2. - 3. - 4. - 5. - 6. - 7. - 8. - **Fabrication of Metals** Fabrication techniques include forming, casting, powder metallurgy, welding, and machining. **Forming Operations** 1. 2. 3. 4. **Casting** Molten metal is poured into molds: - - - - - **Heat Treatment** Processes to alter metal properties: 1. 2. 3. 4. 5. 6. **MODULE 7** ------------ **CERAMICS** - - **STRUCTURES AND PROPERTIES OF CERAMICS** **Ceramic Bonding** 1. 2. **Ceramic Crystal Structure** 1. 2. 3. 4. 5. 6. **Mechanical Properties of Ceramics** **Typical Properties of Ceramics** - - - - - - - - - - - - - - **Classification of Ceramics** 1. 2. 3. 4. 5. 6. 7. **Microelectromechanical Systems (MEMS) -** miniature "smart" systems consisting of a multitude of mechanical devices that are integrated with large numbers of electrical elements on a substrate of silicon. **Nanocarbons -** A class of recently discovered carbon materials that have novel and exceptional properties, are currently being used in some cutting-edge technologies, and will certainly play an important role in future high-tech applications. **Fullerenes -** discovered in 1985, named in honor of R. Buckminster Fuller, who invented the geodesic dome. **Carbon Nanotubes -** have unique and structure-sensitive electrical characteristics. They can be used for flat-screen displays. **Graphene -** the newest member of the nanocarbons, is a single-atomic-layer of graphite, composed of hexagonally sp2 bonded carbon atoms. These bonds are extremely strong, yet flexible, which allows the sheets to bend. **Ceramic Fabrication Technique** 1. - - - - 2. - - - - 3. - - - 4. 5. **MODULE 8** ------------ **POLYMERS** - **Hydrocarbon Molecules** 1. 2. 3. **Isomerism -** Hydrocarbon compounds with the same composition may have different atomic arrangements, a phenomenon termed as isomerism - **Two Isomeric Subclasses** 1. 2. **Polymer Molecules -** molecules in polymers are gigantic in comparison to hydrocarbon molecules; because of their size they are often referred to as macromolecules. **Repeat units - T**hese long molecules are composed of structural entities, which are successively repeated along the chain. **Monomer -** refers to the small molecule from which a polymer is synthesized. - Monomer and repeat unit mean different things, but sometimes the term monomer or monomer unit is used instead of the more proper term repeat unit. **Homopolymer -** When all of the repeating units along a chain are of the same type. **Copolymer -** Chains may be composed of two or more different repeat units. - - - - **Functionality -** number of bonds that a given monomer can form - - **Molecular Structures** - - - - - **Thermoplastics Polymers -** soften when heated (and eventually liquefy) and harden when cooled--- processes that are totally reversible and may be repeated. **Thermosetting Polymers (Thermosets) -** network polymers - **Molecular Weight -** Tensile modulus is relatively insensitive to molecular weight. **Degree of Crystallinity -** both tensile modulus and strength increase with increasing percent crystallinity. **Predeformation by drawing** - Stiffness and strength are enhanced by permanently deforming the polymer in tension. **Heat-treating -** Heat-treating undrawn and semicrystalline polymers leads to increases in stiffness and strength and a decrease in ductility. **Vulcanization -** The crosslinking process in elastomers is called vulcanization, which is achieved by a nonreversible chemical reaction, typically carried out at an elevated temperature. **Crystallization -** During the crystallization of a polymer, randomly oriented molecules in the liquid phase transform into chain-folded crystallites that have ordered and aligned molecular structures. **Melting -** The melting of crystalline regions of a polymer corresponds to the transformation of a solid material having an ordered structure of aligned molecular chains into a viscous liquid in which the structure is highly random. **Glass Transition -** occurs in amorphous regions of polymers. - **Polymer Types** 1. 2. **Miscellaneous Applications** 1. 2. 3. 4. **Molding -** most common method for forming plastic polymers. 1. 2. 3. 4. 5. **MODULE 9** ------------ **COMPOSITES** - - **Classification of Composite Materials** Composite materials are classified into four main divisions: 1. 2. 3. 4. **Particle-Reinforced Composites** 1. - - 2. - - **Fiber-Reinforced Composites** - - - **The Fiber Phase:** 1. 2. 3. **The Matrix Phase:** 1. 2. 3. **Polymer-Matrix Composites (PMCs)** - 1. - - - 2. - - 3. - - **Metal-Matrix Composites (MMCs)** - - - **Ceramic-Matrix Composites (CMCs)** - - **Carbon--Carbon Composites** - - - **Hybrid Composites** - - - **Processing of Fiber-Reinforced Composites** 1. 2. 3. **Structural Composites** 1. - 2. - **Nanocomposites** - - Nano and Biomaterials Intended Learning Outcomes After studying this chapter, you should be able to: 1. 2. 3. 4. **MODULE 10** ------------- **BIOMATERIALS** Biomaterials interface with biological systems to treat, evaluate, or replace damaged body parts. Common materials include metals, polymers, ceramics, composites, and semiconductors. They must be biocompatible, non-toxic, and suitable for specific mechanical requirements. **Metallic Biomaterials** - - - **Polymeric Biomaterials** - - - **Ceramics** - - - **Natural Biomaterials** - - - **Applications of Biomaterials** 1. 2. 3. 4. 5. 6. 7. 8. **Nanomaterials** Nanomaterials have components smaller than 100 nm and unique properties due to their size. These materials include zero-dimensional (nanoparticles), one-dimensional (nanorods), and two-dimensional (thin films). **Types of Nanomaterials** 1. 2. 3. 4. **Properties of Nanomaterials** - - - - **Applications of Nanomaterials** 1. 2. 3. 4. 5. **Production Methods for Nanomaterials** 1. - - 2. - - 3. - - -