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This document discusses materials science and various material properties. It begins by defining materials science and its focus on the internal structure and properties of materials. It then classifies and describes different types of materials like metals, ceramics, polymers, composites, and semiconductors. Various mechanical, thermal, electrical, and other properties of materials are outlined. The document emphasizes that material properties are important for engineering design and that the appropriate material must be selected based on fabrication, service, and economic requirements.
5875206.ppt
- 3. Introduction:- Material is something that consist of matter. Material consist of wide range of metals and non- metals which must be operated upon to form the end product.
- 4. Introduction:- Material science is a scientific discipline which is primarily concerned with the search for the fundamental knowledge about the internal structure, properties and processing of materials. Many and diverse factors have forced a renaissance in materials, Coupled with advances in fundamental science, they have led to new technical area which is known as Science of materials or Material science.
- 5. Based on the Physical and Chemistry of the internal Structure of the material. Investigates relationships betn the structure of material and their properties. Concerns with the inter-disciplinary study of material for engineering and other practical purpose. Deals with all materials. e.g. metals, ceramics, glasses, organic plastics and polymers
- 6. Metallurgy is the science and technology of metals. Metallurgy includes the practice and science of Extracting metals from their ores. Refining of crude metal. Production of alloys and study of their constitution, structure and properties. The relationship of physical and mechanical properties to thermal and mechanical treatment of metal and alloy.
- 7. CLASSIFICATION OF METALLURGY Extractive Metallurgy Mechanical Metallurgy Physical Metallurgy
- 8. Extractive Metallurgy Extractive metallurgy is the study of the extraction and purification of metals from their ores. Mechanical Metallurgy Mechanical metallurgy is the study of the techniques and mechanical properties that shape or make finished forms of metal. Physical Metallurgy Physical metallurgy that deals with structure of metals and alloys with the aim of designing and producing those structures that give the best properties.
- 11. Metals are composed of elements which readily give up electrons to provide a metallic bond and electrical conductivity. this forms large no. of delocalized electron which are free to move within a structure of metals. When two or more pure metals are melted together to form a new metal is called alloy. E.g. Ferrous :-Cast Iron, Steels etc.. Non-ferrous:-Cu, Al, Zn, Sn. etc. Cupro – Nickel alloy
- 12. Due to Their electric properties they are used in electric wire and Electrical devices . Stainless steel alloy is milled into coils, sheets, plates, bars, wire, and tubing to be used in cookware, hardware , surgical instruments. Brass can be used for the metallic coatings of several lock ,Watch etc.
- 13. Luster surfaces Hardness Low specific heat Plastic deformability Good thermal and electrical conductivity Relative high melting point Strength Ductility Malleability Opaquity Stiffness Machinability etc.
- 14. Ceramics are compounds of metallic and non metallic elements. Usually consist of oxides, carbides, or borides of various metals.Ceramic materials are rock Or clay mineral material. Ceramic are any inorganic, non-metallic solids (or super cooled liquids) processed or used at high temp. E.g. Mgo,SiO2,glasses,Sand,Cements, Concrete etc. TYPES OF CERAMICS 1.Whitewares clays 2.Refaracotories Have high Silicon or Aluminium oxide content. 3.Abrasives. Natural garnet, diamond, Silicon carbide.
- 15. WHITE WARES are used in including tableware, wall tiles, pottery products and sanitary ware REFRACTORIES are used in making fire bricks silica crucible and ovens. Due to there low thermal conductivity and high strength to temperature Sandpaper is a very common coated abrasive.
- 16. Brittleness Rock-like appearance Hardness Abrasiveness Insulation Corrosion Resistance Opaque to light Withstand high Temp. about 1000 °C to1600°C.
- 17. polymers are normally composed of carbon compounds. these organic compounds chemically consists of carbon, hydrogen, oxygen, nitrogen or any other non metallic elements bonded together by strong covalent bond forming long molecular chain. A-A-A-A-A-A-A-A-A-A-A-A-A-A-A-A-A-A-A-A-A-A-A-A E.g. Rubbers, plastics, papers, fuels, Wood, Lubricants, etc….
- 18. Polypropylene the polymer we are using from morning to night
- 19. Light Weight Soft Ductile Combustible Non Dimensionally Stable Poor Conductors of Heat and Electricity Poor Resistance to temperature.
- 20. Composite material consist of more than one material type. A composite is designed to display a combination of the best characteristics of each of the component materials. Fiberglass is the best example of composites. it acquires its strength from the glass and flexibility from the polymers.
- 22. Carbon fiber composites with polymer matrices, have become the advanced composite materials for aerospace, due to their high strength, high Modulus and low cost. Helmet and bullet proof jacket Made Up of Aramide Composite material Fiber-reinforced plastics have reached the stage where they could be used for making wheels.
- 23. Semiconductors have electrical conductivity between the electrical conductors and insulators. Integrated circuits Micro controller
- 24. Si wafer in photovoltaic cells to convert light energy to electric energy. Semiconductor memory uses semiconductor-based integrated circuits to store information. A transistor is a semiconductor device used to amplify and switch electronic signals
- 26. ENGINEERING REQUIREMENTS OF MATERIAL Fabrication Requirements Service Requirements Economics Requirements
- 27. Fabrication requirements means that material should be get shaped(e.g., cast, forged, formed, machined, sintered etc) and joined(e.g. welded, brazed. Etc.) easily. Service requirement implies that the material selected for the purpose must stand up to service demand. e.g., proper strength, wear resistance, corrosion resistance, etc. Economics requirements demand that the engineering part should be made with minimum overall cost. Above three are the basic Engineering Requirements to produce any of the engineering components.
- 28. Material property is a qualitative and quantitative measure of response of materials to externally imposed condition. E.g. forces, temperature etc. Properties render a material suitable or unsuitable for particular use in industry. The material property is independent of the dimension or shape of the material. There are hundreds of properties that are measured in laboratories for the purpose of comparing materials. Some of the most important properties are grouped as under.
- 29. MATERIAL PROPERTIES MECHANICAL PROPERTIES THERMAL PROPERTIES ELECTRICAL PROPERTIES MAGNETIC PROPERTIES CHEMICAL PROPERTIES OPTICAL PROPERTIES PHYSICAL PROPERTIES TECHNOLOGICAL PROPERTIES
- 31. The properties of a material that determine its behaviour under applied forces are known as mechanical properties. A sound knowledge of mechanical properties of material provide the basis for predicting behaviour of metal under different load condition. Important mechanical properties are:- Elasticity Plasticity Stiffness Ductility Malleability Brittleness Resilience Yield strength Impact strength Tensile strength Fatigue Creep Wear resistance Hardness toughness
- 32. ELASTICITY The tendency of a deform solid to seek its original dimensions upon unloading is called elasticity. Elastic means reversible. After unloading if recovery is complete then it is perfectly elastic material. if recovery is incomplete then called inelastic material F bonds stretch return to initial Area(A) Load(F) Stress length(A) Original L) length( in change Strain
- 33. PLASTICITY Plasticity is the property of a material by virtue of which it may be permanently deform when it has been subjected to an externally applied force great enough to exceed the elastic limit.
- 34. TOUGHNESS Toughness is the ability of a material to absorb energy during plastic deformation up to fracture. Toughness is the ability of a material to withstand bending or the application of shear stresses without fracture. Copper is extremely tough but cast iron is not. smaller toughness- unreinforced polymers Engineering tensile strain, Engineering tensile stress, smaller toughness (ceramics) larg er toughness (metals, PMCs)
- 35. RESILIENCE Resilience is closely related to toughness. Resilience is the capacity of a material to absorb energy when it is elastically deform then upon unloading, to have this energy recovered. It represents the ratio of energy given up on recovery from deformation to energy required to produce deformation. TENSILE STRENGTH In a tensile test, the ratio of the maximum load to original cross section area is called tensile strength. Tensile strength is a measure of strength and ductility of material.
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- 38. IMPACT STRENGTH The capacity of material to resist or absorb shock energy before it fractures is called its impact strength. Ductile material possess higher impact strength than brittle materials. YIELD STRENGTH When metals are subjected to tensile force, they stretch and elongate as the stress increases, the point where the stretch suddenly increase, is known as the yield strength of the material.
- 39. MALLEABILITY Malleability is the capacity of material to undergo deformation under compression without rupture. The ability of a metal to be deform by hammering or rolling is called malleability. Lead is a good example of malleability but gold is most malleable. HARDNESS Hardness is the resistance of a material to plastic deformation usually by indentation. The term may be refer to stiffness for resistance to elastic deflection. Molecular solids such as plastics are relatively soft, metallic and ionic solids are harder than molecular solids and covalent solids are hardest material known.
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- 41. DUCTILITY Ductility refers to the capacity of material to undergo deformation under tension without rupture. Ductility is the ability of a material to be drawn from a large section to small section such as in wire drawing. BRITTLENESS Brittleness is defined as a tendency to fracture without appreciable deformation. Brittle material will fracture with little permanent deformation/distortion.
- 43. FATIGUE When subjected to fluctuating or repeated loads material tends to develop a characteristics behaviour which is different from that under study load, fatigue is the phenomenon that leads to fracture under such condition. Fracture takes place under repeated or fluctuating stresses whose maximum value is less than the tensile strength of material. Fatigue fracture is progressive ,beginning as minute cracks that grow under the action of the fluctuating stress.
- 44. CREEP It is defined as the time-dependent and permanent deformation of materials when subjected to a constant load or stress. Materials are often placed in service at elevated temperatures and exposed to static mechanical stresses deformation under such circumstances is termed creep. WEAR RESISTANCE Wear is the unintentional removal of solid material from rubbing surfaces. i) Adhesive wear ii) Abrasive wear Adhesive wear referred to as scoring, is an intensive interaction between two bearing surfaces resulting from mutual adhesion of metals at the junction. Abrasive wear is the removal by plowing from the surface of material by another body much harder than abraded surface.
- 46. Thermal property is meant the response of a material to the application of heat . It is very necessary to know the thermal behaviour of those materials which are to be used in making component parts of furnaces, oven or boilers that has to withstand steady high or fluctuating temperature. Important thermal properties are:- Heat capacity Specific heat Thermal expansion Thermal conductivity Melting point
- 47. HEAT CAPACITY:- It indicates ability of a material to absorb heat from external surrounding. The amount of the heat required to produce unit temperature rise is termed as heat capacity of the material. SPECIFIC HEAT Specific heat is the quantity of heat that must be added to a unit mass of the solid to raise its temperature by one degree.
- 48. Thermal Expansion:- Change of temperature of material cause change in its dimensions. this phenomenon is called the thermal expansion. Melting Point The temp. at which solid phase of material transform into liquid is called as melting point. The material having stronger chemical bond have higher melting point. Thermal Conductivity:- Amount of heat flowing per unit time through cross section area of the elements when temp. difference between two ends of elements is unity.
- 50. The characteristics of a material relative to its interaction with light are termed as optical properties. Important thermal properties are:- Reflectivity :- Reflectivity is the property by virtue of which reflection of light from interface occurs. Refractivity:- Refraction is bending of the light beam upon entering to one medium from another due to change in speed between two media. Reflectivity Refractive index Absorptivity Scattering
- 52. Scattering :- The discontinuity in crystal such as grain boundaries, twin boundaries, non metallic inclusion etc. deflects the light beam in different direction which is termed as scattering of beam. Absorptivity:- Absorptivity is the property by virtue of which material absorbs a part of the total light energy absorbs on it.
- 53. The total energy radiation is 1. R + S + T + A = 1 R= Energy reflected from material. S= Energy scattered from material. T= Energy transmitted from material. A= Energy absorbed from material.
- 55. Those qualities which give information regarding the suitability of metals for various technological operations or processes are called technological properties. Such properties are highly desirable in shaping. Forming and fabrication of material. Important technological properties are:- Castability Machinability Weldability Solderability Workability
- 56. CASTABILITY It is the ease with which the material can be given various solid shape from liquid state. Castability allows metal and alloy ,when molten, to fill a mould so as to give a flawless casting. Steps in casting : 1. Melt the metal 2. Pour it into a mold 3. Let it freeze
- 57. MACHINABILITY Machinability is defined as the ease with which a given material can be cut or removed by cutting tools in machining operation, with satisfactory finishing at lowest cost. Machinability depends upon Chemical composition of material Microstructure Mechanical properties Cutting condition etc.
- 58. WELDABILITY It is defined as the capacity of the metal to be welded under the fabrication condition imposed in a specific suitably designed structure and to perform satisfactory in the intended service. Good Weldability means that the weld is free from pores, slug, inclusions, cracks etc.
- 59. WORKABILITY OR FORMABILITY The ability of metal indicating the ease with which it can change its shape while in solid stage is called workability or formability. It is based on ductility of metal which in turn is based on its crystal structure, grain size, hot and cold working. etc. Workability has separate consideration for different forming processes like rolling, forging, extrusion, drawing, spinning, stretch forming.
- 62. Physical properties are characteristics of materials that are determined by nature. Physical properties do not require the material to be deformed or destroyed in order to determine value of the properties. Important physical properties are:- Dimensions Colour Appearance Density Porosity Structure
- 63. DIMENSIONS:- Includes size, shape & tolerances of materials Size is determined by breadth, width, length, diameter etc. Shape is determined by section of the material like square, circular, triangular, I section etc. Tolerances are determined based on the accuracy of size and shape required of the component during manufacture.
- 64. POROSITY:- A material is said to be porous if it has pores within it. STRUCTURE:- Structure means geometric relationship of material component. It implies, electron structure(on a subatomic level) crystal structure(on an atomic level) microstructure(on a microscopic level) volume (Total) Bulk volume pore Total porosity True
- 66. Most of the engineering materials, when they come in contact with other substance with they can react ,tends to suffer from chemical deterioration, this necessitates the study of chemical properties. Important chemical properties are:- COMPOSITION:- Composition of a material can be determined by analytical chemistry. In metals and alloy the percentage of various elements which make up metals and alloy decides the compositions. Cartridge brass has 70% Cu & 30% Zn. Composition Structure Corrosion resistance
- 67. STRUCTURE:- this usually refers to a microstructure of a material. microstructure is a component seen when metal is examined under a microscope. CORROSION RESISTANCE:- Corrosion is the deterioration of a material by chemical reaction with its environments. Corrosion affects both metallic as well as non-metallic materials like bricks, concrete, etc. Example rusting of irons, corrosion of concrete by sulphates in soils.
- 69. Resistivity Conductivity Semi conductivity Super conductivity Dielectric strength Resistivity:- The property of the material to oppose the flow of current through it is defined as resistivity of material. Conductivity It is reciprocal of resistivity. The property of the material to which the electrical current flows easily through the material it is defined as resistivity of material.
- 70. Semi conductivity:- A material which is neither a good conductor nor a good insulator is defined as semiconductor. Super Conductivity The electrical resistivity of the material disappears at or near absolute zero temperature the material is then called super conductor and the property is called super conductivity. Dielectric Strength:- Dielectric strength is the minimum voltage which when applied to insulating material results in destruction of its insulating properties.
- 72. Magnetic Permeability:- The ratio of magnetic induction or magnetic flux density(B) To the magnetic field strength(H) is termed as magnetic permeability(μ). Magnetic permeability is the measure of ease with which material can be magnetized. Coercive force:- The opposite magnetizing force required to remove residual magnetization of the material is termed as coercive force. For the soft magnetic material this force should be as low as possible because they are temporary magnets. For permanent magnets it should be high.
- 73. Hysteresis:- Hysteresis can be defined as the lag in the change of magnetization behind variation of the magnetic field. If a ferromagnetic material subjected to increasing or decreasing magnetic fields. the change in flux density(B) plotted against the magnetic force(H) result in hysteresis loop.
- 74. Factors affecting the selection of engineering materials Properties of Materials Performance Requirements Material’s Reliability Safety Physical Attributes Environments condition Availability Disposability and Recyclability Economic Factors
- 75. The properties of material define specific characteristic of material and forms basis for predicting behaviour of material under different conditions. It includes mechanical, electrical, thermal. physical, chemical, magnetic etc. Properties of Materials Performance Requirements The material of which a part is composed must be capable of embodying or performing a part’s function without failure. For example, for a component part to be used in a furnace must be of that material which can withstand high temperature.
- 76. Reliability is the degree of probability that a product, and the material of which it is made, will remain stable enough to function in service for the intended life of the product without failure. For example if mild steel used instead of stainless steel will result in failure in corrosive environment. Material’s Reliability Safety A material must be safely perform its function For example if a material is selected which is brittle and used at low temp. in pressure vessels, bridges, ships & pipe lines will be unsafe due to brittle fracture. it will be avoided at any cost because it produces disastrous consequences.
- 77. Physical attributes such as configurations, size, weight, and appearance sometimes also serve functional requirements. For instant the functioning of a gyroscope or a flywheel is directly related to weight of material used. Physical Attributes Environments condition The environment in which a product operates strongly influences service performance. Humidity, water, or chemicals can cause corrosion and subsequent failure of materials.
- 78. Materials must be available in large enough quantity, for the intended application. In times of scarcity this constraint becomes significant. In the future, with the projected scarcity of many material resources, this constraint will assume increasing importance. Availability Disposability and Recyclability Disposability of nuclear material is very important. Recycling is the process of remanufacture large pieces of equipment from scrap material.
- 79. Cost, perhaps more often than any other constraint. The original cost of material for a given application is made up of two components. The cost of a material and the cost of a processing the material into finished parts. In every application, there is a cost beyond which one can not go that prescribes the limit that can be paid for a material to meet the application requirements. Economic Factors