Naval Material Reviewer PDF

NAVAL MATERIAL REVIEWER MODULE 1: NATURE OF MATERIALS c. Energy/Environmental - Next generation energy conversion Material Science - It involves investigating the...

NAVAL MATERIAL REVIEWER MODULE 1: NATURE OF MATERIALS c. Energy/Environmental - Next generation energy conversion Material Science - It involves investigating the d. Information Technology - Materials relationships that exist between the structures and informatics properties of materials. Four Components of Materials Science Materials Engineering - Application of material science in designing or engineering the structure of a material to 1. Structure produce a predetermined set of properties. 2. Properties 3. Performance Materials Development: 4. Processing 1. Stone Age (beginning life – 3000 BC) - using naturally occuring materials with Characterization - the heart of the tetrahedron. only changes in shape. 2. Bronze Age (3000 BC – 1200 BC) Material Selection Process - Copper and Tin Alloy - Ability to modify materials by refining 1. Application - determine required properties. (using heat), chemical modifications 2. Properties - identify candidate materials. (alloying) and mechanical deformation 3. Material - Identify required processing. (cold working) 3. Iron Age (1200 BC – Present) Materials Choosing - Casting and alloying weren’t perfected until 16th century Mastery of Steel (Iron 1. In service requires alloy) technology enables Industrial - Strength hardness Revolution in the 18th and 19th century. - Thermal - Ability to heat treat at high temperature, - Resistant, ductility control microstructure at different length 2. Economic requires scale and ability to design specific - Material cost, machine cost, process microstructures for specific properties time. 4. Plastic Age (1940 – Present) 3. Industrial requires - Discovery of polymers, and the ability to - Easily parts assemble machine ability of synthesize and process polymers. running, cast properties 5. Silicon Age (1950 - Present) 4. Deteriorate of materials - Commercialization of silicon technology - Wear, oxidation, corrosion. (integrated circuits, electronic devices, etc...) leads to the information age, which 1.1 Types of Engineering Materials gives boost to human productivity - Ability to control alloying accurately, Classification of materials: ability to make thin films. 1. Metallic 6. Future - material that exhibits electrical and a. Nanotechnology - Synthesis and thermal conductivity. characterizations of nanomaterials and - most significant role in the industrial nanostructure operations b. Biotechnology - biomimetics and 2. Non-metallic biomaterials - wood, stone, brick, cement, resins (plastics), rubber, leather, ceramics etc. METAL - Synthetic polymer materials such as nylon, - combinations of metallic elements. polyethylene, Teflon, and silicone have for the - quite strong, yet deformable. basis for a burgeoning polymer industry - forms cations and ionic bonds with non-metals. - crystalline structure COMPOSITE - relatively strong and ductile at room temperature - Mixture of two or more materials. and maintain good strength even at high - Consists of selective filler or reinforcing material temperature. and a compatible resin binder to obtain specific 1. Ferrous - include steel, cast iron, wrought and properties desired. iron, malleable cast iron and iron-base - Fiberglass is a familiar example. metal. - Plywood is a commonly encountered composite 2. Non-ferrous - include all other metals and material. their combination such as copper, tin, zinc, aluminum, magnesium and SEMICONDUCTOR MATERIAL titanium. - Solid or liquid material that conducts electricity and heat at room temperature. CERAMIC - Have electrical properties that are intermediate - compounds between the non-metallic and between the electrical conductors and insulator. metallic elements chemically bonded together. - At low temperatures, pure semiconductors - Most frequently oxides, nitrides, and carbides. behave like insulator. - Composed of clay minerals, cement, and glass - silicon, germanium, selenium, gallium, arsenide, - crystalline and non-crystalline or mix zinc selenide and lead telluride. - Advantages include light weight, high strength - This means conductivity roughly in the range of and hardness, good heat and wear resistance, 10^3 to 10^−8 siemens per centimeter. reduces friction and insulative properties. - foundation of modern electronics, including - insulative to the passage of electricity and heat. radio, computers, telephones, etc. - Hard but not brittle - transistors, solar cells, many kinds of diodes - comes from the Greek word "κεραμικός" including the light-emitting diode, the (keramikos), "of pottery" or "for pottery", from silicon-controlled rectifier, and digital and analog "κέραμος" (keramos), "potter's clay, tile, pottery" integrated circuits. which is said to derive from the Indo-European - Silicon is used to create most semiconductors word *cheros (unattested), meaning heat. commercially. POLYMERS BIOMATERIAL - plastics and rubber materials. - Employed in components into the human body - Chemically based on carbon, hydrogen and for replacement of diseased or damage body another non-metallic element. parts. - Low density and may be extremely flexible. - These materials does not produce toxic - derived from the Greek words “poly” meaning substances and must be compatible with body "many"; and “meros” meaning "part". tissues. - non-crystalline but some consists of mixture of - Biomaterials are used in: both - Joint replacements - Some are good insulators and are used for - Bone plates electrical insulation applications. - Bone cement - Natural polymers exist such as cellulose, which - Dental implants for tooth fixation is the main constituent of wood and paper. - Contact lenses - Synthetic polymers include synthetic rubber, - Breast implants Bakelite, neoprene, nylon, PVC, polystyrene, polyethylene, polypropylene, polyacrylonitrile, PVB, silicone, etc. NANOENGINEERED MATERIALS - Ionic bonding is termed nondirectional; - “Nano” materials are single units sized between that is, the magnitude of the bond is 1 and 1000 nanometers (10−9 meter) but is equal in all directions around an ion. usually 1—100 nm. Materials with structure at - The predominant bonding in ceramic the nanoscale often have unique optical, materials is ionic. electronic, or mechanical properties. - to develop mechanical, electrical, magnetic, and 2. Covalent Bonding other properties that are not otherwise possible. - Sharing of electrons between adjacent We call this the “bottom-up” approach. atoms. - the study of the properties of these materials is - The covalent bond is directional; that is, it termed “nanotechnology” is between specific atoms and may exist - carbon nanotube only in the direction between one atom and another that participates in the electron sharing. 1.2 Engineering Material Composition 3. Metallic Bonding - Arises from the electrostatic attractive Atomic Structure force between conduction electrons and - Each atom consists of a very small nucleus positively charged metal ions. composed of protons and neutrons, which is - sharing of free electrons among a encircled by moving electrons. structure of positively charged ions. - Atomic number (Z): number of protons in the nucleus. Secondary Bonding or Van Der Waals Bonding - Uranium: the highest of the naturally occurring - Secondary, van der Waals, or physical bonds elements with 92 atomic numbers. are weak in comparison to the primary or - Atomic mass (A): the sum of the masses of chemical ones. protons and neutrons within the nucleus. - Exists between virtually all atoms or molecules, - Isotopes: elements that have two or more but its presence may be obscured if any of the different atomic masses. three primary bonding types is present. - Atomic weight: corresponds to the weighted - Evident in inert gases, which have stable average of the atomic masses of the atom’s electron structures, or between molecules in naturally occurring isotopes. molecular structures that are covalently bonded. - Atomic mass unit (amu): used for computations of atomic weight. - 1 amu = 1/12 of the atomic mass of the most common isotope of carbon. - The atomic weight of an element or the molecular weight of a compound may be specified as amu per atom (molecule) or mass per mole of material. - 1 mol = 6.023 x 10^23 atoms or molecules. - 1 amu/atom (or molecule) = 1 g/mol 1.3 Chemical Bonding Primary Interatomic Bonds 1. Ionic Bonding - One atom donates electrons to the other. - Sodium chloride (NaCl) (SALT) is the classic ionic material.  MODULE 2: STRUCTURE OF - The number of atoms per unit cell (N): CRYSTALLINE SOLIDS N = Ni + Nf/2 + Nc/8 - sss Where: Crystalline material Ni = the number of interior atoms - atoms are situated in a repeating or periodic Nf = the number of face atoms array over large atomic, long-range order exists. Nc = the number of corner atoms - atoms position themselves in a repetitive - Two other important characteristics of a three-dimensional pattern, in which each atom is crystal structure are the coordination bonded to its nearest neighbor atoms. number and the atomic packing factor Non-crystalline/Amorphous Material (APF). - do not crystallize and the long-range atomic - Atomic packing factor (APF): the sum of order is absent. the sphere volumes of all atoms within a unit cell divided by the unit cell volume. 2.1 Crystals Structure - APF = volume of atoms in a unit cell / Total unit cell volume Crystal Structure - For FFC,, the atomic packing factor is - the manner in which atoms, ions, or molecules 0.74 for spheres all having the same are spatially arranged. diameter. Atomic hard-sphere model 2. Body Centered Cubic (BCC) - where spheres representing nearest-neighbor - has a cubic unit cell with atoms located atoms touch one another. at all eight corners and a single atom at Lattice the cube center. - a three-dimensional array of points coinciding - Unit cell length (a): a = 4R /√3 with atom positions (or sphere centers). - Number of atoms per BCC unit cell is 2. UNIT CELLS - The coordination number for the BCC - small groups of atoms form a repetitive pattern. crystal structure is 8. - are parallelepipeds or prisms having three sets - Atomic packing factor is lower for of parallel faces; one is drawn within the BCC—0.68 versus 0.74 (FCC). aggregate of spheres which in this case - Simple cubic (SC): happens to be a cube. - a unit cell that consists of atoms - basic structural unit or building block of the situated only at the corners of a crystal structure and defines the crystal structure cube. by virtue of its geometry and the atom positions - The only simple-cubic element is within. polonium, which is considered to METALLIC CRYSTAL STRUCTURES be a metalloid (or semi-metal). - The atomic bonding in this group of materials is 3. Hexagonal Close-Packed metallic and thus non directional in nature. - The top and bottom faces of the unit cell consist of six atoms that form regular 3 simple crystal structures hexagons. in common metals: - Another plane that provides three additional atoms to the unit cell is 1. Face-Centered Cubic (FCC) Crystal Structure situated between the top and bottom - found for many metals has a unit cell of planes. They have the nearest neighbors cubic geometry, with atoms located at atoms in both of the adjacent two planes. each of the corners and the centers of all - N = Ni + Nf/2 + Nc/6 the cube faces. - 6 atoms are assigned to each unit cell. - copper, aluminum, silver, and gold. - Cube edge length (a): a = 2R√2  2 types of point defects 2.1 Crystalline and Non-crystalline Materials in solid solutions 1. Substitutional - solute or impurity atoms Single Crystal replace or substitute for the host atoms. - when the periodic and repeated arrangement of 2. Interstitial atoms is perfect or extends throughout the entirety of the specimen without interruption. Four (4) Hume–Rothery rules Polycrystalline - Most crystalline solids are composed of a 1. Atomic size factor collection of many small crystals or grains. - Appreciable quantities of a solute may be Grain Boundary accommodated in this type of solid - An area where some atomic mismatch within the solution. region where two grains meet. 2. Crystal structure Noncrystalline Solids - For appreciable solid solubility, the - lack a systematic and regular arrangement of crystal structures for metals of both atom atoms over relatively large atomic distances. types must be the same. - Sometimes such materials are also called 3. Electronegativity factor amorphous (meaning literally “without form”), or - The more electropositive one element supercooled liquids, inasmuch as their atomic and the more electronegative the other, structure resembles that of a liquid. the greater the likelihood that they will form an intermetallic compound instead of a substitutional solid solution. MODULE 3: IMPERFECTIONS OF SOLIDS 4. Valences - a metal has more of a tendency to POINT DEFECTS dissolve another metal of higher valency than to dissolve one of a lower valency. Vacancy - The simplest of the point defects, one normally Dislocation occupied but from which an atom is missing. - a linear or one-dimensional defect around which Self-interstitial some of the atoms are misaligned. - an atom from the crystal that is crowded into an Edge Dislocation interstitial site—a small void space that under - a linear defect that centers on the line that is ordinary circumstances is not occupied. defined along the end of the extra half-plane of atoms. Impurities in Solids Screw Dislocation - The addition of impurity atoms to a metal results - being formed by a shear stress that is applied to in the formation of a solid solution and/or a new produce the distortion when the upper front second phase, depending on the kinds of region of the crystal is shifted one atomic impurity, their concentrations, and the distance to the right relative to the bottom temperature of the alloy. portion. Solid solution Burgers Vector - forms when the solute atoms are added to the - Used to express the magnitude and direction of host material, the crystal structure is maintained the lattice distortion associated with a and no new structures are formed. dislocation. - Is compositionally homogeneous. Interfacial Defects - are boundaries that have two dimensions and normally separate regions of the materials that  have different crystal structures and/or Scanning Electron Microscopy (SEM) crystallographic orientations. - The surface of a specimen to be examined is Grain Boundary scanned with an electron beam. - represented schematically from an atomic Scanning Probe Microscopy (SPM) perspective within the boundary region, which is - the microscope generates a topographical map, probably just several atom distances wide, there on an atomic scale, that is a representation of is some atomic mismatch in a transition from the surface features and characteristics of the crystalline orientation of one grain to that of an specimen being examined. adjacent one. Tilt Boundary Grain Size - One simple small-angle grain boundary is - often determined when the properties of formed when edge dislocations are aligned in polycrystalline and single phase materials are the manner. under consideration. Twist Boundary - may be specified in terms of average or mean - When the angle of misorientation is parallel to grain diameter. the boundary, which can be described by an array of screw dislocations. Two (2) common grain-size determination techniques Phase Boundary - exists in multiphase materials, in which a 1. Linear Intercept different phase exists on each side of the - counting numbers of grain boundary boundary. intersections by straight test lines. Twin Boundary 2. Comparison - a special type of grain boundary across which - comparing grain structures with there is a specific mirror lattice symmetry. standardized charts. Volume Defects - are defects in 3-dimensions. These include pores, cracks, foreign inclusions and other MODULE 4: DIFFUSION IN SOLIDS phases. Atomic Vibrations - every atom in a solid material is vibrating very Diffusion rapidly about its lattice position within the crystal. - Mass transport by atomic motion. Microstructure - the net movement of anything (for example, - grain size and shape atoms, ions, molecules, energy) from a region of higher concentration to a region of lower MICROSCOPIC TECHNIQUES concentration. Interdiffusion / Impurity Diffusion Optical Microscopy - The process by which atoms of one metal - the light microscope is used to study the diffuse into another. microstructure; optical and illumination systems Self-Diffusion are its basic elements. - The process by which all atoms exchange positions are of the same type. ELECTRON MICROSCOPY Transmission Electron Microscopy (TEM) - formed by an electron beam that passes through the specimen. DIFFUSION MECHANISM MODULE 5: PROPERTIES AND Vacancy Diffusion CHARACTERISTICS OF MATERIALS - involves the interchange of an atom from a normal lattice position to an adjacent vacant PHYSICAL PROPERTIES lattice site or vacancy. Interstitial diffusion Density - involves atoms that migrate from an interstitial - implies the weight of a material, with higher position to a neighboring one that is empty. density rates implying heavier materials. Porosity of Materials Fick’s First Law - When material is in melting condition, it contains - Diffusion is a time-dependent process, the some dissolved gasses within the material. quantity of an element that is transported within - represents the quantity of voids in solid another is a function of time. materials. Diffusion Flux (J) Melting Point - defined as the mass (or, equivalently, the - the minimum required temperature for a solid number of atoms) M diffusing through and material to change into liquid. perpendicular to a unit cross-sectional area of Color solid per unit of time. - the reflective property of a material. Steady State Diffusion Boiling point - First Law - the minimum required temperature for a liquid - The mass of diffusing species entering the plate material to change into gas. The boiling point of on the high-pressure side is equal to the mass water in standard condition is 100C or 212F. exiting from the low-pressure surface—such that Size and shape there is no net accumulation of diffusing species - Dimension of any metal reflect shape and size of in the plate. material, length, width, height, depth etc. Also, it Steady State determines specific rectangular, circular, - The diffusion condition for which the flux is spherical, or any other section. independent of time. Specific gravity Concentration Gradient - ratio of density of material with respect to density - The driving force for steady-state diffusion. of reference material or substance. Unsteady State Diffusion MECHANICAL PROPERTIES - Fick’s Second Law, the partial differential equation. Stress and Strain - There is a net accumulation or depletion of - The mechanical behavior of the material may be diffusing species, and the flux is dependent on ascertained by a simple stress-strain test. time. Engineering Stress - Stress is defined as the instantaneous load divided by the original specimen cross sectional area. Tension Test - During this test, gradually increasing tensile load is applied uniaxially along the long axis of a specimen. Compression Test - is conducted in a manner that the force is compressive and the specimen contracts along the direction of the stress. Shear Test Resilience - performed using a pure shear force. - the ability of material to absorb the energy when Torsion Test it is deformed elastically by applying stress and - a variation of pure shear in which a structural release the energy when stress is removed. member is twisted. Toughness Engineering Strain - the ability of material to absorb the energy and - strain is expressed as the change in length (in get plastically deformed without fracturing. the direction of load application) divided by the Hardness original length. - the ability of material to resist permanent shape Elastic deformation change due to external stress. - Hardenability - the ability of a material to attain the hardness by Stress-Strain Behavior heat treatment processing. - The degree to which a structure deforms or Brittleness strains depends on the magnitude of an imposed - indicates how easily it gets fractured when it is stress. subjected to a force or load. Poisson’s ratio (v) Malleability - is defined as the ratio of the lateral and axial - property of solid material which indicates how strains. easily a material gets deformed under Plastic Deformation compressive stress. - occur when the stress is removed, the material Creep and Slip does not return to its previous dimension, it is a - property of material which indicates the permanent, irreversible deformation. tendency of material to move slowly and deform Tensile Properties permanently under the influence of external - can be determined using tensile testing. The mechanical stress. properties can be easily explain using the Fatigue stress-strain diagram. - the weakening of material caused by the repeated loading of material. Proportional Limit - It is the region in the strain curve which obeys CHEMICAL PROPERTIES hookes law. Elastic Limit pH - It is the point in the graph up to which the - a measure of the acidity or basicity of a solution. material returns to its original position when the Hygroscopy load acting on it is completely removed. - the ability of a substance to attract and hold Yield Stress Point water molecules from the surrounding - defined as the point at which the material starts environment. to deform plastically. Surface tension Ultimate Stress/Tensile Strength - a property of the surface of a liquid that allows it - It is the point corresponding to the maximum to resist an external force. stress that a material can handle before failure. Reactivity Breaking Point - refers to the rate at which a chemical substance - It is the point in the stress strain curve at which tends to undergo a chemical reaction in time. the failure of the material takes place. Corrosion Resistance Ductility - Resistant to corrosion - a property of a solid material which indicates how easily a material gets deformed under tensile stress.  THERMAL PROPERTIES MAGNETIC PROPERTIES Heat Capacity Magnetism - property that is indicative of a material’s ability to - the phenomenon by which materials exert an absorb heat from the external surroundings; it attractive or repulsive force or influence on other represents the amount of energy required to materials. produce a unit temperature rise. Magnetic dipoles Specific Heat Capacity - are found to exist in magnetic materials, which, - the heat capacity per unit mass of a material. in some respects, are analogous to electric Molar Heat Capacity dipoles. - the heat capacity per mole of a pure substance Magnetic field strength (H) (J/mol-K). - the externally applied magnetic field. Thermal Expansion Magnetic flux density (B) - a material property that is indicative of the extent - represents the magnitude of the internal field to which a material expands upon heating. strength within a substance that is subjected to Thermal Conductivity an H field. - the property that characterizes the ability of a Permeability material to transfer heat. - a property of the specific medium through which Thermal Stresses the H field passes and in which B is measured. - stresses induced in a body as a result of Diamagnetism changes in temperature. - a very weak form of magnetism that is nonpermanent and persists only while an ELECTRICAL PROPERTIES external field is being applied. Paramagnetism Ohm’s Law - For some solid materials, each atom possesses - time rate of charge passage to the applied a permanent dipole moment by virtue of voltage (V). incomplete cancellation of electron spin. Electrical Conductivity Ferromagnetism - indicative of the ease with which a material is - Certain metallic materials possess a permanent capable of conducting an electric current. magnetic moment in the absence of an external Electrical Resistivity field and manifest very large and permanent - the reciprocal of electrical Conductivity. magnetizations. Capacitance Antiferromagnetism - When a voltage is applied across a capacitor, - Magnetic moment coupling between adjacent one plate becomes positively charged and the atoms or ions also occurs in materials. other negatively charged. Ferrimagnetism Permittivity - Some ceramics also exhibit a permanent - the measure of how much resistance is magnetization. encountered when forming an electric field in a Electromagnetic radiation medium. - considered to be wavelike, consisting of electric Dielectric Constant and magnetic field components that are - The relative permittivity. perpendicular to each other and also to the Dielectric Strength direction of propagation. - represents the magnitude of an electric field necessary to produce breakdown.  OPTICAL PROPERTIES Rockwell Scale - a hardness scale based on indentation hardness Radiation Density of a material. - Radiation intensity expressed in watts per Bend Test square meter, corresponds to the energy being - are used to determine internal weld quality transmitted per unit of time across a unit area coupons. that is perpendicular to the direction of - Three (3) types of bend test: propagation. 1. Face bend (face of the weld is tested) Transparent - places the greatest amount of - Materials that are capable of transmitting light stress on the weld face. with relatively little absorption and reflection. 2. Root bend (root of the weld is tested) Translucent - places the greatest amount of - Materials are those through which light is stress on the weld root. transmitted diffusely. 3. Side bend (sides of the weld is tested) Opaque - places the greatest amount of - Materials that are impervious to the transmission stress along the weld axis. of visible light. Tensile Test Refraction - used to compare the weldment to the base metal - the phenomenon in which light that is mechanical values and specification transmitted into the interior of transparent requirements. materials experiences a decrease in velocity, and, as a result, is bent at the interface. Tensile tests are made to determine the following: Reflection - When light passes from one transparent medium 1. Ultimate strength of the weld to another. - This is the point at which the weld fails Absorption under tension. - 2. Yield strength of the weld - This is the point at which the weld yields or stretches under tension and will not MODULE 6: MATERIAL TESTING return to its original dimensions. 3. Elongation DESTRUCTIVE TESTING - This is the amount of stretch that occurs - Prolonged endurance testing under the most during the tensile test. It is measured by severe operating conditions, continued until the placing gauge marks on the sample or component, equipment, or product specimen coupon before testing and comparing the fails (is broken or destroyed). after-break distance with the original Destructive Physical Analysis (DPA) gauge marks. - are carried out to the specimen's failure, in order to understand a specimen's performance or Notch Toughness Test material behavior under different loads. - a method used to quantify a material's ability to Poldi Hardness Test withstand an impact with a flaw present in the - the simplest and most economical device for material. measuring hardness according to Brinell. Nick-Break Test Rockwell Hardness Test - a type of destructive testing that is used to - measure the depth of penetration of an indenter evaluate the quality of a weld. under a large load (major load) compared to the penetration made by a preload (minor load). NON-DESTRUCTIVE TESTING (NDT) Ultrasonic Imaging - the process of doing inspections, testing, or - High resolution images can be produced by evaluating materials, components or assemblies plotting signal strength or time-of-flight using a for defects without destroying the material or computer-controlled scanning system. component. Eddy Current Testing - particularly well suited for detecting surface Who Uses NON-DESTRUCTIVE TESTING? cracks but can also be used to make electrical 1. Airline and Aerospace conductivity and coating thickness 2. Automotive and Railroad measurements. 3. Construction Pressure Test 4. Hydroelectric, Fossil, and Nuclear Power - A test that subjects a vessel, tank, piping, or 5. Textile and Manufacturing tubing to internal pressure. 6. Chemical and Petrochemical Ferrite Test 7. Logistics and Supply - determines the amount of magnetic ferrite in an 8. Medical and Pharmaceutical austenitic (nonmagnetic) weld. Six (6) NDT Methods: DIFFERENCE BETWEEN DESTRUCTIVE AND NON-DESTRUCTIVE TESTING 1. Visual Test 2. Liquid Penetrant Test NON-DESTRUCTIVE DESTRUCTIVE TEST 3. Magnetic Test TEST 4. Ultrasonic Test 5. Eddy Current Test Used for finding out Used for finding out the 6. X-ray Test defects of materials properties of the material Load is not applied on Load is applied on the Visual Testing (VT) the material material - the most commonly used test method where visual observation is done to the surface to No load applications, so Due to load application, evaluate the presence of surface discontinuities no chance for material material gets damaged such as corrosion, misalignments, cracks, etc. damage Liquid Penetrant Test (PT) No requirement of Special equipment is - uses a liquid with high surface wetting special equipment required characteristics. Magnetic Flux Leakage (MFL) Non expensive Expensive - detects anomalies in normal flux patterns Less skill Skill is required created by discontinuities in ferrous material saturated by a magnetic field. Radiography - Uses a higher energy version of the electromagnetic waves that we see as visible light. Film Radiography - The part is placed between the radiation source and a piece of film. Ultrasonic Inspection - High frequency sound waves are introduced into a material and they are reflected back from surfaces or flaws.