Crystallography and Material Science Quiz

Introduction to Chemistry of Engineering Materials

• Engineering materials are vital to our existence, daily needs, and survival
• Gold was the first metal used by humans, followed by copper
• Science areas relating to materials include: Engineering Materials, Materials Science, and Materials Engineering

Basic Concepts of Crystal Structure

• Crystalline solids' properties depend on crystal structure: the arrangement of atoms, ions, or molecules within the material.
• Space lattice (or lattice) is a repeating pattern of points in three-dimensional space.
• Lattice point represents each atom in the lattice structure.
• Lattice array is the arrangement of lattice points
• Lattice space is the space covered by lattice points
• Unit cell is a small, repeating volume that represents the crystal structure's symmetry.
• Unit cells can be defined as a finite representation of an infinite lattice, a small repeat entity, the basic structural unit, and a building block of the structure.
• Lattice parameters (a, b, c, α, β, γ) define the unit cell's size and angles: typically measured in Angstroms (Å) or nanometers (nm).
• 7 crystal systems (cubic, hexagonal, tetragonal, orthorhombic, monoclinic, rhombohedral, and triclinic) are defined based on the relationships among lattice parameters.
• Bravais lattices are 14 types of crystal system where presented, and their arrangement is determined with the inclusion of Centering.

Metallic Crystal Structures

• Simple Cubic (SC): Atoms are located at the corners of a cube.
• Body-Centered Cubic (BCC): Atoms are located at the corners and center of a cube.
• Face-Centered Cubic (FCC): Atoms are located at the corners and face centers of a cube.
• Hexagonal Close-Packed (HCP): Atoms form regular hexagons in layers with a half-hexagon of atoms between each layer.

Crystallographic Directions

• Crystallographic directions are represented by vectors with coordinates [uvw]. These are determined by subtracting coordinates of the initial and end point of the vector in a crystal structure.
• Hexagonal crystal direction is represented by [xyuz] and can be converted to [XYZ] by applying the formula.

Properties of Crystals

• Coordination number is the number of nearest neighbor atoms or ions surrounding an atom or ion in a crystal structure
• Atomic Packing Factor is measure of the closeness of packing of atoms in a unit cell, calculated as volume of atoms divided by volume of the unit cell.
• Planar Density is the density of atomic packing on a particular plane in a crystal structure.
• Linear Density is the number of atoms per unit length along a particular direction in a crystal structure.

Metals

• Metals are employed for various engineering purposes and requirements. Iron is one of the most popular metals in engineering.
• All metals have a crystalline structure.

Alloys

• An alloy is a mixture or compound of two or more elements (at least one being metallic).
• Alloying enhances some properties, including strength and hardness, of these materials.
• Solid solutions: one element is dissolved in another, often characterized as substitutional or interstitial.
• Intermediate phase: a phase where its chemical composition is intermediate between the two pure elements, and its crystalline structure is different from these elements.

Importance of Metals

• High stiffness and strength are achieved. These properties are especially useful in engineering applications.
• Toughness allows metals to better absorb energy compared to other materials.
• Good electrical and thermal conductivity of metals is useful for conducting electricity and heat effectively, respectively.
• Cost-effectiveness is important for metal selection in engineering applications.

Metals Used in Manufacturing Process

• Cast metal: the starting form is a casting
• Wrought metal: the metal has been worked or can be worked after casting
• Powdered metal: the starting form is very small powders for conversion into parts using powder metallurgy techniques.

Classification of Metals

• Ferrous metals: contain iron as a main constituent. These are cast iron, wrought iron, and steel. Classification depends on carbon content.
• Non-ferrous metals: do not contain iron. Examples are aluminum, copper, tin, zinc, and lead.

Ferrous Metals

• Cast iron: contains 2 to 4.23% carbon; has harder characteristics. Types include: Gray cast iron, white cast iron, chilled cast iron, malleable cast iron, and toughened cast iron.

• Wrought iron: almost pure ion with 0.15% carbon. Has soft and heat-workable properties

• Steel: an iron alloy with a carbon content of up to 2.0%. Types include: Low carbon (mild) steel, Medium carbon steel, and High carbon steel.

Alloy Steel

• Steel with additional elements (other than carbon) to enhance specific properties. Example: Chromium, cobalt, Manganese, Tungsten, Vanadium, Nickel steels.

Non-ferrous Metals

• Aluminum, Copper, Tin, Zinc, Lead: Detailed properties and uses for each metal.

Super Alloys

• Alloys possessing superior properties at high temperatures
• Three groups of superalloys: Iron-based, Nickel-based, and Cobalt-based.
• They have excellent high-temperature properties, such as strength, hardness, creep resistance, and corrosion resistance.
• Used in high-temperature applications (e.g., jet engines, gas turbines, and power plants).

Metal Processing

• Metal processing (including quenching, annealing, tempering, cold working) affects mechanical properties.
• Metal manufacturing process affects mechanical properties, which can be affected by factors like grain size.
• The different processing methods affect mechanical properties: annealing softens and cold working hardens metals.
• Different cold working processes are defined

Metal Manufacturing: Production

• Casting, powder processing, and forming are different approaches used in producing metals.

Metal Manufacturing: Fabrication

• Deformation, machining, and joining (includes welding, brazing, bolting, and adhesives) are methods for shaping metals.
• These methods are essential to producing finished products.
• Finishing processes (galvanization, powder coating) are the last steps in manufacturing.

Mechanical Properties of Materials

• Strength, Elasticity, Plasticity, Ductility, Tensile strength definition and explanations
• Stress (normal, shearing, bearing stress. Stress definition and formula for each stress.
• Simple strain (formula and explanation, concept)
• Stress-strain diagram (showing the different properties of the material -elastic range, plastic range, yield point, ultimate strength and rapture).
• Explanation of the stress-strain diagram.

Polymers

• Polymers are high-molecular-weight materials created from repeating monomer units. Examples are Polyethylene (PE), Polypropylene (PP), Polyvinyl Chloride (PVC), Polystyrene (PS).
• Types of polymerization: chain-reaction and step-reaction (condensation).
• Polymer branching affects properties (high-density, low-density, linear-low-density polyethylene).
• Polymer linking: homopolymers and copolymers (alternating, random, block copolymers)
• Polarity influences material properties including melting point, solubility, barrier properties, and coefficient of friction.
• Molecular structure and properties are explained

Nanomaterials

• Nanotechnology: a scientific field dealing with materials at the nanoscale.
• Types and uses of nanomaterials.
• Methods of nanomaterial manufacturing: top-down and bottom-up approaches; chemical vapor deposition, molecular beam epitaxy, atomic layer epitaxy, dip pen lithography, nanoimprint lithography, roll-to-roll processing, self-assembly. Manufacturing properties of nanomaterials that are discussed.
• Potential effects of nanomaterials on health and environment: effects on humans, animals, and on the environment.

Test your knowledge on crystallography and material science with this quiz. Explore concepts like coordination numbers, atomic packing factors, and the properties of different crystal structures. This quiz covers essential topics for students in materials science and engineering.