Engineering Materials Lecture 1 PDF

23/09/2024 MEU11E12. Engineering Materials and Their Applications 1 Lecture 1 Categories of Materials Amir Pakdel – School of Engineering, Trinity College Dublin https://pakdelgroup.weeb...

23/09/2024 MEU11E12. Engineering Materials and Their Applications 1 Lecture 1 Categories of Materials Amir Pakdel – School of Engineering, Trinity College Dublin https://pakdelgroup.weebly.com Useful Reading 2 Textbooks:  The Science and Engineering of Materials by Donald R. Askeland  Materials by Michael F. Ashby et al.  Engineering Materials (1, 2) by Michael F. Ashby et al.  Any other books about mechanical properties. Amir Pakdel – School of Engineering, Trinity College Dublin https://pakdelgroup.weebly.com 1  23/09/2024 What’s This Module About? 3  This module is about materials. Materials are used in all fields of engineering: civil, mechanical, manufacturing, biomedical, electronics, etc.  This module is an introduction to: Types of Properties of Materials Materials Relationship between Materials Types and Properties Amir Pakdel – School of Engineering, Trinity College Dublin https://pakdelgroup.weebly.com What’s This Module About? 4  For example: Steel is STRONG. Glass is BRITTLE. Diamond is HARD. Rubber is DUCTILE. Common What are properties in material each material categories? category The origin of specific properties in different material categories Amir Pakdel – School of Engineering, Trinity College Dublin https://pakdelgroup.weebly.com 2  23/09/2024 What’s This Module About? 5  I am going to introduce the mechanical properties of materials, which are essential for understanding how materials behave under load: STIFFNESS , STRENGTH , TOUGHNESS , HARDNESS  I will also tell you about Fracture & Failure in materials.  If time allows, I will also tell you about how materials gradually degrade and fail over long periods of time, as a result of: WEAR , CREEP , FATIGUE , CORROSION (otherwise, you will learn about these in Year 3 of your studies) Amir Pakdel – School of Engineering, Trinity College Dublin https://pakdelgroup.weebly.com Materials & Their Mechanical Properties 6 Amir Pakdel – School of Engineering, Trinity College Dublin https://pakdelgroup.weebly.com 3  23/09/2024 Classes of Materials 7 Ceramic Metals Metal Composite Polymers (man-made) Composites Ceramics  Based on the atomic structure and Ceramic properties, materials can be divided into four main categories. Polymer Composite (natural) Amir Pakdel – School of Engineering, Trinity College Dublin https://pakdelgroup.weebly.com 1st Class of Materials 8  The most common class of engineering materials is Metals & Alloys. Metals: Include a single element, e.g. iron (Fe), aluminum (Al), copper (Cu), titanium (Ti), platinum (Pt), gold (Au), etc Amir Pakdel – School of Engineering, Trinity College Dublin https://pakdelgroup.weebly.com 4  23/09/2024 1st Class of Materials 9  The most common class of engineering materials is Metals & Alloys. Alloys: made by combining elements. o steel = iron (Fe) + carbon (C) o brass = copper (Cu) + zinc (Zn) o bronze = copper (Cu) + tin (Sn) o solder = tin (Sn) + lead (Pb) Metals & Alloys: strong and tough, heavy and expensive. This artificial hip joint is made from an alloy of cobalt and chromium, because Co-Cr alloys have high toughness and good corrosion resistance. Amir Pakdel – School of Engineering, Trinity College Dublin https://pakdelgroup.weebly.com 2nd Class of Materials 10  Polymers: Typically organic materials made of non-metallic elements such as C, H, O, N, S, Cl.  Consisting of very large molecules that are composed of many repeating units. The repeating unit (Monomer) (Polymer) Examples: natural rubber, different plastics, polyethylene (PE), polycarbonate (PC). Polymers: light and cheap… can be soft and bio-friendly … also strong enough for day- PMMA contact lens PP child seat to-day applications. Poly(methyl methacrylate) Polypropylene Amir Pakdel – School of Engineering, Trinity College Dublin https://pakdelgroup.weebly.com 5  23/09/2024 2nd Class of Materials 11  Recyclable Polymers: Not all polymers can be recycled. Below are examples of recyclable polymers. (no need to memorize) Amir Pakdel – School of Engineering, Trinity College Dublin https://pakdelgroup.weebly.com 3rd Class of Materials 12  Ceramics: Ceramic materials are inorganic, non-metallic solids. They are hard and usually brittle. They have very high melting points  heat-resistant. They have excellent chemical stability  oxidation-resistant. Ceramic materials are usually composed of metal oxides, carbides, or nitrides. e.g. Aluminum Oxide (Al₂O₃), Tungsten Carbide (WC), Silicon Nitride (Si₃N₄) Common examples: cement, clay, tiles, rocks, bricks, diamonds. Amir Pakdel – School of Engineering, Trinity College Dublin https://pakdelgroup.weebly.com 6  23/09/2024 3rd Classes of Materials 13  Ceramics: Glass is another important ceramic material. Note: It is stiff and quite strong. Window glass and sand But it is brittle and has low toughness*. are both mainly made of silicon dioxide (SiO2). (*we will learn about toughness soon.) Amir Pakdel – School of Engineering, Trinity College Dublin https://pakdelgroup.weebly.com 4th Class of Materials 14  Composites: Made by combining materials from the other three classes. Why: To mix the properties of different materials. Simple examples: (1) Chocolate bars (2) Toothpaste o Chocolate: Sweet & smooth o Abrasive Particles: Clean/polish teeth o Nuts: Crunchy & nutritious o Gel Base (with fluoride): Strengthens teeth & holds particles together Amir Pakdel – School of Engineering, Trinity College Dublin https://pakdelgroup.weebly.com 7  23/09/2024 4th Class of Materials 15  Composites: Made by combining materials from the other three classes. Why: To mix the properties of different materials. Engineering examples: (1) Reinforced concrete (2) Fiberglass o Matrix  Concrete o Reinforcement  Thin Glass Fibres Strong under pressure Strong & stiff, but brittle o Reinforcement  Steel o Matrix  Resin Strong under stretching o Flexible, insulator, & holds fibres together Amir Pakdel – School of Engineering, Trinity College Dublin https://pakdelgroup.weebly.com 4th Class of Materials 16  Composites: Made by combining materials from the other three classes. Why: To mix the properties of different materials. Natural composite examples: (1) Bone (2) Wood o Multiple components o Multiple layers Amir Pakdel – School of Engineering, Trinity College Dublin https://pakdelgroup.weebly.com 8  23/09/2024 Classes of Materials 17 Metals & Polymers Alloys Composites Ceramics & Glasses + Semiconductors Nanomaterials Natural materials Silicon Ceramic nanotubes Wood Germanium Metal nanowires Leather Gallium Arsenide Polymer nanoparticles Bone Polyaniline (PANI) Composite nanostructures Cotton, Wool, Silk Polypyrrole (PPy) Sand, Stone, Rock Amir Pakdel – School of Engineering, Trinity College Dublin https://pakdelgroup.weebly.com 1st Sub-Class of Materials 18  Semiconductor: A material with electrical conductivity between that of a conductor (like metals) and an insulator (like plastics).  Mainly used in electronics, optics, and related industries. (e.g. diodes, transistors, solar cells, LEDs, …)  You are going to learn more about semiconductors later in this module (electronic part). Amir Pakdel – School of Engineering, Trinity College Dublin https://pakdelgroup.weebly.com 9  23/09/2024 2nd Sub-Class of Materials 19  Nanomaterials: Have at least one dimension in the nanometre scale. (1 nm = 10-9 m = one million times smaller than 1 mm on a ruler)  You are going to learn more about nanomaterials later in year 4/5 (Nanotechnology Module).  Famous examples: Graphene A flat layer of carbon atoms. Carbon nanotube A rolled-up layer of carbon atoms. o Incredibly strong (much stronger than steel) o Excellent conductors of electricity and heat. Amir Pakdel – School of Engineering, Trinity College Dublin https://pakdelgroup.weebly.com 3rd Sub-Class of Materials 20  Natural materials: Found in nature, not significantly altered by human processes. o Plant-based: wood, cotton, bamboo, rubber o Animal-based: wool, silk, leather, bone, ivory o Mineral-based: stone, clay, sand, salt Bamboo building Amir Pakdel – School of Engineering, Trinity College Dublin https://pakdelgroup.weebly.com 10  23/09/2024 Classes of Functional Materials 21  Classification based on: the type of functionality specific properties particular applications 1. Electronic materials 2. Magnetic materials 3. Optical materials 4. Energy materials 5. Smart materials 6. Biomedical materials 7. Aerospace materials 8. Structural materials Amir Pakdel – School of Engineering, Trinity College Dublin https://pakdelgroup.weebly.com Summary 22 Topics discussed in Lecture 1:  Main categories of materials Metals & Polymers  Introduction to their: Alloys Composites o properties o applications Ceramics & Glasses + Semiconductors Nanomaterials Natural materials  Further reading: The Science and Engineering of Materials, Donald Askeland, Chapter 1 Amir Pakdel – School of Engineering, Trinity College Dublin https://pakdelgroup.weebly.com 11  23/09/2024 Lecture Slides (Available on BlackBoard) 23 Amir Pakdel – School of Engineering, Trinity College Dublin https://pakdelgroup.weebly.com 12