Material Science Lecture 1 PDF

Material Science Lecture 1 Salsabil mohammed Materials: is a substance that humans have assembled or produced as products, appliances, inventions , various constructions. Material Science : material science involves investigating the relationships that exist between the structures and properties...

Material Science Lecture 1 Salsabil mohammed Materials: is a substance that humans have assembled or produced as products, appliances, inventions , various constructions. Material Science : material science involves investigating the relationships that exist between the structures and properties of materials.the role of a materials scientist is to develop or synthesize new materials, Materials Engineering : materials engineering involves on the basis of these structure–property correlations, designing or engineering the structure of a material to produce a predetermined set of properties.materials engineer is called upon to create new products or systems using existing materials and/or to develop techniques for processing materials. Material Evolution material science : material science involves investigating the relationships that exist between the structures and properties of materials.the role of a materials scientist is to develop or synthesize new materials, processing - how materials are shaped into useful components to cause changes in the properties of different materials. structure- relates to the arrangement of atoms. properties - relates to the materials shape and size. performance - be the function of its properties.  1.Structure the structure of a material usually relates to the arrangement of its internal components. Subatomic structure : involves electrons within the individual atoms and interactions with their nuclei. On an atomic level, structure encompasses the organization of atoms or molecules relative to one another. microscopic: meaning that which is subject to direct observation using some type of microscope. macroscopic: structural elements that can be viewed with the naked eye  2. properties Virtually all important properties of solid materials may be grouped into six different categories: 1. Mechanical properties relate deformation to an applied load or force; examples include elastic modulus (stiffness), strength, and toughness. 2. Electrical properties, such as electrical conductivity and dielectric constant. 3.Thermal properties such as heat conduction efficiency 4.Magnetic properties demonstrate the response of a material to the application of a magnetic field. 5.Optical properties, the stimulus is electromagnetic or light radiation; index of refraction and reflectivity are representative optical properties. 6.Deteriorative characteristics means the chemical reactivity of material , such as ( corrosion ) CLASSIFICATION OF MATERIALS: Solid materials have been conveniently grouped into three basic categories: metals, ceramics, and polymers, a scheme based primarily on chemical makeup and atomic structure. Most materials fall into one distinct grouping or another. In addition, there are the composites that are engineered combinations of two or more different materials. Another category is advanced materials—those used in high-technology applications, such as semiconductors, biomaterials, smart materials, and nanoengineered materials  Metals Metals are composed of one or more metallic elements (e.g., iron, aluminum, copper, titanium, gold, nickel), and often also nonmetallic elements (e.g., carbon, nitrogen, oxygen) in relatively small amounts. Metallic materials have large numbers of nonlocalized electrons—that is, these electrons are not bound to particular atoms. Many properties of metals are directly attributable to these electrons. For example, metals are extremely good conductors of electricity and heat, and are not transparent to visible light; a polished metal surface has a lustrous appearance  Polymers Polymers include the familiar plastic and rubber materials. Many of them are organic compounds that are chemically based on carbon, hydrogen, and other nonmetallic elements (i.e., O, N, and Si). Furthermore, they have very large molecular structures, often chainlike in nature, that often have a backbone of carbon atoms. Some common and familiar polymers are polyethylene (PE), nylon, poly(vinyl chloride) (PVC), properties : good electrical insulation some tube are heat insulation. High flexibility , light weight , low strength.  Ceramics Ceramics are compounds between metallic and nonmetallic elements; they are most frequently oxides, nitrides, and carbides. For example, common ceramic materials include aluminum oxide ,silicon nitride , and, in addition, what some refer to as the traditional ceramics—those composed of clay minerals (e.g., porcelain), as well as cement and glass properties : insulting heat and electricity high temperature resistance more durable in a toxic environment than metal and polymers is strong but fragile  Composites A composite is composed of two (or more) individual materials that come from the categories previously discussed—metals, ceramics, and polymers. The design goal of a composite is to achieve a combination of properties that is not displayed by any single material and also to incorporate the best characteristics of each of the component materials One of the most common and familiar composites is fiberglass, in which small glass fibers are embedded within a polymeric material (normally an epoxy or polyester).The glass fibers are relatively strong and stiff (but also brittle), whereas the polymer is more flexible. Thus, fiberglass is relatively stiff, strong , and flexible. In addition, it has a low density. ADVANCED MATERIALS: Another materials category is the advanced materials that are used in high-tech applications, including : 1. semiconductors (having electrical conductivities intermediate between those of conductors and insulators), 2. biomaterials (which must be compatible with body tissues), 3. smart materials (those that sense and respond to changes in their environments in predetermined manners), 4. nanomaterials (those that have structural features on the order of a nanometer, some of which may be designed on the atomic/molecular level). Thank you