ENGINEERING MATERIALS Property name Property description – Explain what the word means Engineering Application – give a practical application of the property in an engineering context Mechanical Tensile strength The resistance of a material to breaking under tension.
Elevator cable. Shear strength In engineering, shear strength. Is the strength of a material or component against the type of yield or structural failure where the material or component fails in shear. Ultrasonic welding to join phones. Compressive strength The resistance of a material to breaking under compression Pillars for bridges. Hardness Resistance of a material to deformation, indentation, or penetration by means such as abrasion, drilling, impact, scratching. Drill bit.
Toughness The state of being strong enough to withstand adverse conditions or rough handling. Hammer. Ductility Solid material’s ability to deform under tensile stress; this is often characterized by the material’s ability to be stretched into a wire. Copper wires. Malleability The quality of something that can be shaped into something else without breaking. Shaping sheet metal into a car body panel. Elasticity The ability of an object or material to resume its normal shape after being stretched or compressed.
An example for this is rubber tyres for a vehicle. Brittleness When subjected to stress, it breaks without significant deformation (strain). Brittle materials absorb relatively little energy prior to fracture, even those of high strength. Shatter glass on fire alarm. Physical Density The degree of compactness of a substance.
Boats so they float on water. Melting temperature The temperature at which a given material changes from a solid to a liquid. Soldier to join wires in circuit boards.
Thermal Expansion Thermal expansion is the tendency of matter to change in shape, area, and volume in response to a change in temperature. Expansion gaps on train tracks. Conductivity The rate at which heat passes through a specified material. Radiators. Electrical and magnetic Resistivity A measure of the resisting power of a specified material to the flow of an electric current. Resistors. Conductivity The degree to which a specified material conducts electricity. Electrical wires.
Permeability The ability of a substance to allow another substance to pass through it Coiled wire inside a step up and step down transformer. Permittivity 1. The ability of a substance to store electrical energy in an electric field. Capacitor PROPERTIES MATERIAL MECHANICAL PHYSICAL THERMAL ELECTRICAL MAGNETIC PACTICAL APPLICATION MILD STEEL Modulus of Elasticity (Typical for steel) – 205 GPa. Tensile Strength, Yield 370 MPa Density (?) 0.9 g/cm3 – 1.53 g/cm3 : median 1.07 g/cm3 Thermal Conductivity Btu / (hr-ft-F)-Steel, mild 26.
0 – 37.5. Melting point 2570oF. Steel, like any other metal, conducts electricity because metals are electropositive elements.
All common carbon or mild steel, low alloy steels, and tool steels are ferromagnetic. Machine tools Large structures – bridges, buildings, oilrigs. 0.4% CARBON STEEL Tensile Strength, Yield 310 MPa. Tensile Strength Ultimate 565 MPa Density- 7.87 g/cc Thermal Conductivity Btu / (hr-ft-F) – 136. Melting point 1220oF. Steel, like any other metal, conducts electricity because metals are electropositive elements.
All common carbon or mild steel, low alloy steels, and tool steels are ferromagnetic. Skyscrapers, bridges, ALUMINIUM Aluminium alloys have tensile strengths of between 70 and 700 MPa It is light, with a density one third that of steel, 2,700 kg/m3 Melting Point 582 – 652 °C. Specific Heat Capacity 0.896 J/g-°C Aluminium is an excellent conductor of electricity and weighs half as much as a copper conductor. Aluminium can become slightly magnetic but in everyday experience, it does not exhibit magnetism.
Aircraft Bicycles ABS Tensile Strength, Yield 42.5 – 44.8 Mpa. Flexural Modulus 2.25 – 2.28 GPa Density 1.04 g/cc Vicat Softening Point 100 °C Electrical insulation properties. Non-magnetic.
Commonly used for injection moulding applications POLYPROPYLENE Tensile strength 33 Mpa. Tensile modulus 1.4 GPa.
Lightest thermoplastics (density 0.905 g cm-3). A crystallinity of ca 50-60%. PP has a melting point of 171 °C N/A Non-magnetic. Pipes, containers CFRP The modulus of carbon fibre is (228 GPa). Ultimate tensile strength is (3.
5 GPa). Could not find information Carbon Fibre thermal conductivity 21-180 N/A Non-magnetic. Performance racing bicycles, Formula I car bodies CONCRETE Tensile strength – ? : 2 – 5 Mpa Compressive strength : 20 – 40 MPa Density – ? : 2240 – 2400 kg/m3 Concrete has a very low coefficient of thermal expansion, and as it matures concrete shrinks. N/A Non-magnetic. House foundations. Walls. NITINOL Ultimate tensile strength 895 Mpa.
Young’s modulus approx. 83 GPa Density (g/cc) 6.5 Melting Point 1310oC. Electrical Resistivity (µ?-cm) 76 (M) / 82 (A) Non-magnetic. Dental braces Mild steel- Phase equilibrium diagram showing eutectic structure Mild steel is made from carbon and iron. The most relevant region on the graph is up to 2% carbon. The mechanical properties of steel are affected by the amount of carbon content in the alloy. In the liquid phase, carbon is completely soluble but only partially soluble in solid crystal lattice structures that form as the alloy cools.
Austenite as pure iron cools from 1394oC to 912oC, steel exists in a single phase called austenite. It can dissolve up 2% carbon weight. Ferrite as pure iron cools from 912oC iron forms into a BBC structure. Only 0.02% carbon can be kept in solution with ferrite the rest will then be forced out, the excess carbon forms cementite, which is an intermetallic compound (Fe3C). Cementite is hard and brittle how ever, useful if evenly dispersed through steel. Ferrite and cementite often occur together and form alternating layers or plates.
Mild steel has less carbon atoms inside of the metal compared to high carbon steel. High carbon steel The lattice structure of the high carbon steel has smaller negatively charged carbon atoms between the positively charged iron atoms this creates a magnetic field between the two atoms, which then make it harder for the layers to slide over each other. This structure when heated the structure changes from the layers and when heated the atoms then expand into different sizes and then solidified in that structure the atoms them are much harder to separate, as they cannot slide over each other.
Both tempering and hardening use this principle and heat the metal up until cherry red which is when they quench the metal inside a water or oil bath to cool this then solidifies the irregular structure. Brass There are two substitutional alloys, bronze and brass. In this case, we are looking at brass, and this is where some of the copper atoms in the metal structure are substituted with the substitutional compounds zinc or tin atoms. Nickel aluminide Ordered intermetallic alloy, and a long-range-ordered alloy is a solid-state compound, which shows, metallic bonding.
Many intermetallic compounds are often simply called alloys. Polystyrene When monomers are joined end-to-end like links along a chain, these are linear; Covalent bonds hold the atoms together. This is all through a process called polymerization. A Covalent Bond is a chemical bond that involves the sharing of electron pairs between atoms. Electron pairs are known as bonding pairs, when these electrons share it is known as covalent bonding. The sharing of these electrons allows some atoms to get a full outer shell, which then allows it to become much more stable.
Glass transition is a reversible reaction where materials go from a hard and quite brittle state to a rubbery state as the temperature increases. The melting temperature for polystyrene is 240oC so when it reaches this temperature the material will begin to change state. Polypropylene When these monomers are joined end-to-end like links along a chain, this is a branched or network structure. Covalent bonds hold the atoms together. This is all through a process called polymerization.
Crystallization of polymers is a process associated with partial alignment of the polymers molecular chains. These chains can fold together and form ordered chains these then compose larger structures. Polymers can crystallize upon cooling from the melt, which then locks in those larger structures. Bakelite Cross-linked polymers form long chains, which can be branched or linear; these can then form covalent bonds between the polymer molecules. Since they have covalent bonds, which are much stronger than intermolecular forces, it then produces a much more stable material. Which is how rubber is made; it Is heated up so that the sulphur molecules in the rubber form covalent chains.
This is why rubber tyres are much more durable compared to a rubber band. Aluminium Metals form Giant Metallic Lattices. These are composed of positive metal ions surrounded by a ‘sea’ of Delocalised Electrons. Metallic bonding accounts for many physical properties of metals, such as strength, ductility, thermal and electrical resistivity and conductivity. The first picture is of the element aluminium and the top number is mass number, which tells you how many protons, and electrons are in the atom because both protons and electrons are the same in order to be balanced. The bottom number is the atomic number and if you minus the mass number from the atomic number you get the neutron number. The second picture is of an aluminium atom, this shows the nucleus in the middle, this contains the protons and neutrons, the dots orbiting the nucleus are the electrons, and there are 13 electrons.
Carbon fibre reinforced plastic CFRP is carbon fibre reinforced polymer. It is made from fibres of carbon, which are manufactured by a process called polyacrylonitrile. Each carbon fibre is around 5-10 microns in diameter and have a very high tensile strength. Melamine faced chipboard Lamination is where multiple layers of material are, joined by using, heat, adhesive and pressure which then joins the layers together. Chipboard is made by lamination but uses off cuts from different woods and turning them into chips, which are then stuck together using heat, adhesive and pressure, then a plastic coating is then applied to the top and bottom to enhance the properties e.
g. it makes the material water resistant. By doing this to different materials it enhances their properties, they’re also often called composites. Concrete Most concrete is made up of Portland Cement, aggregates (gravel, crushed stones) and sand. Aluminium oxide Ionic bonds form when an atom gives one or more of it’s electrons to another atom. These bonds are formed between a pair of atoms or between molecules and are the type of bond found in salts. This is so they can get a full out shell in order to become stable.
Aluminium oxide has a giant ionic structure. Aluminium is a metallic element. It is malleable, and ductile due to its polycrystalline structure. Aluminium is made up of crystals, which interlock when the metal is then cooled from molten. Glass Glass can be used in ceramics, by heating it up. This allows rearrangement from a random to an ordered structure and an ordered structure is more stable than a disordered one. A well-known example of a glass-ceramic is the ‘ceramic’ cooker hob, which has been developed to have a thermal expansion coefficient close to zero.
This allows it to be rapidly heated and cooled without generating stresses in the hob material. Nitinol At low temperatures, Nitinol spontaneously transforms to a more complicated monoclinic crystal structure. All crystalline solids are composed orderly arrangements of atoms, ions or molecules. Metallic bonding is a type of chemical bonding that happens when there is a electrostatic force between conduction electrons and positively charged metal ions.
It is often referred to the sharing of free electrons among a lattice of positively charged ions. Metallic bonding accounts for many physical properties of metals, such as strength, ductility, thermal and electrical resistivity and conductivity. Amorphous structures form a regular repeating three-dimensional structure called a crystal lattice, producing a crystalline solid, or they can aggregate with no particular order, in which case they form an amorphous solid