Selection and Characteristics of Materials - Report Example

Material Selection and Testing Student Name: Student Number: Date: Introduction Materials are the basic elements which all processes of manufacturing have to work with. Material selection is the most important factor of any engineering design process. Correct material selection is extremely important for a reliable performance of a product or machine. The process of material selection is a complex task, regardless of whether the material of concern is metal, plastic, wood or stone. It requires a balance between design, manufacturing, service and economic requirements. The main concern is that a part may fail either by breaking or wearing out. For instance, an automobile engine would be expected to last forever were it not for camshafts, gears, piston rings, cylinders, valve guides and bearings wearing out or gear teeth and other moving parts getting broken. Selection of materials also involve evaluating their properties. Understanding of material properties is very useful in determining if a given material will work for a certain application. Having the knowledge of material properties and application requirements is very important if a part designer wants to produce high quality parts economically. Material properties may be modified by changing or varying alloy composition, cold working, heat treatment etc. Testing of materials enables engineers to establish the behavior of materials under different conditions of service, and appropriately advice the design team on a suitable choice of materials in a particular application. Discussion Task 1: The primary factors to be considered and process to be followed when selecting materials in the motor vehicle industry When carrying out material selection for a particular application, the properties of the material must meet the conditions under which the component or part will function and operate in. The primary factors to consider when selecting materials include: material properties, cost and availability, manufacturing process, and environmental effect of the material. All these factors are inter-linked in some fashion and play an important role in selecting materials. 1. Material functional properties: Material properties determine if a given material will meet the expected level of performance. The properties considered here are: i. Physical properties – thermal conductivity, density, electrical conductivity etc. ii. Mechanical properties – strength, hardness, stiffness, toughness, ductility etc. iii. Chemical properties - corrosion resistance, reactivity etc. Physical, mechanical, and chemical properties determine the functional and operational requirements that need to be met by a product. Two materials cannot have the same properties, and therefore, the selection of a material is normally decided based on the best possible combination of properties and the rest of the factors to obtain an optimum solution. For example, in the selection of materials used in building automotive body and chassis, there is emphasis on improving fuel efficiency and GHG emission reduction. Lightweight materials are usually used to improve fuel efficiency. However, such materials must be accompanied by suitable mechanical and chemical properties, such as aluminum. 2. Material cost and availability: When selecting a material for a particular application, it is important to consider the cost and availability of the material, as well as the cost of processing these materials to the final component as part of overall economics. There are three aspects of material cost: actual cost of materials, processing value added, and the cost of designing and testing the component. The cost of a material in the automotive industry determines if the material will be selected for an automobile component. The cost of the material should be appropriate and have multiple sourcing options to cope with competition in the market. This will ensure that once the manufacturing design and technologies have been laid out, it will be economical to continue producing the product in the long run. 3. Processing and manufacturing In selecting a material, one has to consider how the product will be made. Manufacturing properties such as machinability, casting, welding, ease of joining, formability etc. should come into consideration. Having the right material manufacturing properties will ensure that the product becomes technically producible. For example, manufacturing a forged component will require a material with excellent flowability to be able to forge it without cracking. 4. Environmental factors Environmental factors to consider in the selection of a material include: i. The effect of the component on the environment; ii. The effect that the service environment will have on the component; and iii. The effect of manufacturing processing on the environment. One of the most important concerns in the automotive industry are reduction of emissions, protection of resources, and recycling. Thus, the aspect of component recycling should also be taken into account as part of environmental considerations. Countries in the European Union and Asia have issued environmental regulations on automobile end-of-life requirements. The process of selecting materials is a complex interaction between the factors discussed above. For example, the cost will be influenced by how difficult it will be to source and process the material, and the effect a material will have on the environment will depend on its properties. Therefore, if a novel material is to be used for a component, it has to be selected at the design stage, so that the design process is done using the right material properties. The baseline is that engineers involved in the selection process should have a thorough understanding of material properties and processing characteristics. A clear definition of the function of a component to be manufactured should be provided in order to identify the most ideal properties. Consideration of the manufacturing process is essential in attaining a process that is capable of making the desired component shape, with the right accuracy, and at an appropriate cost. In real life, both material selection and processing are considered simultaneously for the reason that not all materials will be compatible with existing processes. For instance, titanium, nickel and steel cannot be die-casted, conventional techniques cannot be used to machine ceramic materials. The complexity of shape may further limit the choice of a given process. Task 2: Research and identify some of the different materials that are used in the manufacture of modern motor vehicles. For each material identified you should state the component, where it is on the motor vehicle, the primary material selection criteria, and into which of the groups below it fits. I. Metallic Materials a) Metals used in making the engine and gear box Metals used to make automotive engine and gear box are cast iron, graphite cast iron, aluminum alloys, and Carbon steel and steel alloys. Cast iron – These metals are used to build the engine block – the main housing many engine parts. The primary selection criteria of these materials is their durability, strength and resistance to wear and low weight. These increases power and efficiency of the engine. Steel and steel alloys– These are typically used in building crankshafts. Their selection is based on a combination of the most desirable properties such as strength, durability and wear resistance. High performance crankshafts are also built using nickel-chrome alloy because of its fatigue properties and very high strength, coupled with good impact resistance and ductility at high strengths. Compacted graphite cast iron – This metals are used in making connecting rods and engine block, especially where low weight is a major concern. Materials used to build other automobile parts such as body, chassis, door, IP beam, and bonnet etc. include magnesium, Magnesium – This metal is used in building automobile body and is selected because of its light-weight – 33% lighter than Al and 75% lighter than Cast iron/steel components. Magnesium alloys have better manufacturability, higher machinability, faster solidification, and longer die life compared to steel and iron components. Sintered steel- These metals are used to make sintered steel for bearing components and transmission parts. The desired property of this material is its high resistance to wear Aluminum- Aluminum is used in building automobile body structure and chassis due to its high strength to weight ratio. Another criteria for selection of this metal is recyclability, improvement of energy efficiency, and safety – it can absorb crash energy twice the mild steel. II. Ceramic Materials Alumina ceramics – This is used in structural building for components such as brake disks, particulate filter, pump components, mechanical seals etc. They are very robust and reliable materials, thus, suitable for making a variety of car components. Stabilized Zirconia ceramics – These are used in functional ceramics for components such as sensors, fuel injection systems, PTC heaters, etc. The electrical and thermal properties of these materials enable them to be used in making these components. Generally, ceramics are more cost-efficient compared to metals, and are more durable compared to plastics. III. Composite Materials Carbon fiber composites – This composite material is selected when high strength/low weight ratio is desired. Carbon fiber composites weigh about 20% of steel and are good in terms of strength and stiffness. They never undergo corrosion and can significantly contribute to fuel economy by reducing car weight. Carbon fiber is used in monocoque chassis assembly, wheels etc. Fiber glass composites – These material is very light compared to steel and aluminum. It is rust proof and can easily be shaped. Glass fiber composites are used to make body panel liners, engine compartments, body work, and other external and internal parts. IV. Polymer Materials Thermoplastic Olefin (TPO) – This is used to make impact absorber, thrust washers, bushings, and seal rings. These material remains stable at temperatures above 200oC, and can handle temporary loss of friction. It has superior corrosion resistance. Polycarbonate/ABS – This polymers are used to make door outer panel, middle and overhead console, glove box, knee bolster, pillars, wear pads and other structural components. Together with reduction in weight, the combination of low coefficient of friction, low wear rate, excellent corrosion resistance properties of these polymers improve the overall transmission efficiency. V. Smart materials An example of mart materials used in the automotive industry are shape alloy metals such as copper-zinc-aluminum alloys, copper-aluminum-nickel alloys, and nickel-titanium allows. The choice of these materials is because they can reduce automotive weight and product complexity. Components made from these materials include sensors and actuators with the ability to enhance automotive performance and fuel economy. Task 3: From the components you have identified in section 2 you are required to discuss in detail the composition(inc macro/microstructure), characteristics, properties and manufacturing methods (including how these may affect the properties of the component) used to produce one component from the metallic, ceramic, polymer and composite group respectively. (Approximately 500 words each plus diagrams, images and quotes) 1. Metallic Materials – Cast Iron Cast iron is primarily made up of iron-carbon alloys containing between 2% and 5% carbon. It is typically composed of iron, carbon and silicon, and traces of sulphur, phosphorous and magnesium. The most common form is grey cast iron. The strength of cast iron is dependent on the carbon morphology. The carbon in grey cast iron is present as plates of graphite – the weakest form of cast iron. The carbon in ductile cast iron is presented as graphite spheres – forming the strongest form of cast iron. Another form of cast iron is the white iron. White iron is iron carbide – a very hard and brittle metal. In most cases, pats of casted iron that are to be subjected to wear undergo chilling to convert that particular sport to white iron. The other form of cast iron is malleable cast iron - a white iron subjected to a heat treatment process to produce irregular grains of carbon. This type of cast iron can easily be machined and selectively hardened. Microstructure Cast iron has a crystalline structure and tends to fracture when under tensile loading. Hardness and brittleness of cast iron increases as the graphite content reduces. The main feature of grey iron is the presence of graphite flakes. The graphite flakes give a distinctive grey color to gray iron when fractured. In contrast, white iron has a silvery structure. The shape and size of graphite play a significant role on the structure and properties of iron. Other elements present in iron also affects the structure and properties of the resulting iron matrix. The microstructure of ductile iron is the discrete form of graphite nodules. Ductile iron is formed by alloying – a process that converts graphite flakes into nodules. This transforms the microstructure of the material to create a metal with superior elongation and ductility characteristics. The diagrams below show the microstructures of typical cast iron. Figure 1: Microstructure of cast iron Properties and Characteristics of Cast iron The properties of cast iron are largely determined by its composition, and the manufacturing methods. Pure iron is soft and weak, but hardness increases as carbon and silicon content increases. It is the form of carbon present in cast iron that influences its properties and subsequently, its applications. The rate of cooling during the process of solidification after thermal treatment and the influence of alloying elements determines the form that carbon takes in cast iron. The metal corrodes by rusting process. Manufacturing Methods Cast iron is manufactured by its traditional method – the casting process. In this process, iron ore undergoes heating in a blast furnace to deoxidize and remove impurities and produce a molten state. The molten iron is molded into the desired shape, allowed to cool and crystallize. 2. Ceramic materials – Alumina ceramics Alumina (Al2O3) is an engineering material that offers a combination of good electrical properties and mechanical properties – which makes it have a wide range of applications. In its different purity levels, the material find uses more often compared to any other ceramic material. There are two varieties of alumina – fine and coarse-grained varieties. This advanced ceramic material find applications in heavy-duty forming tools, electronics industry (resistor cores), substrates, tiles and ballistics, textile industries (thread guides), seals for water taps and regulator disks for valves, lighting systems (heat sinks), catalytic carriers in chemical industries, and protection tubes. Structure of Alumina ceramics Alumina has a crystal structure that is commonly known as corundum (Al2O3) – a thermodynamically stable form of alumina. The oxygen ions form a nearly hexagonal close-packed structure. Alumina ions occupy two-thirds of the octahedral interstices (see figure 2). Each aluminum ion center is octahedral. Corundum has a trigonal Bravais lattice crystallography with a space group of R-3c. The primitive cell has two formula units of Al2O3. Alumina also exists in other phases: the cubic γ and η phases, the hexagonal χ phase, the monoclinic θ phase, the δ phase, and the orthorhombic κ phase (Shirai, Watanabe, Fuji, & Takahashi, 2009). These phases can be orthorhombic or tetragonal and each has a different crystal structure and properties. Figure 2: (a) Alumina structure, (b) top-view of alumina structure, (c) octahedral structure of alumina. Figure 3: Course and fined grain structures of alumina Properties of Alumina Ceramics Good electrical insulator Moderate to high mechanical strength (300-650MPa) High hardness (15-19GPa) and high stiffness High compressive strength (2000-4000MPa) Moderate thermal conductivity Excellent gliding properties High wear and corrosion resistance Low density (3.75-3.95oC) High operating temperatures (1000-1500oC) Durable due to high mechanical strength, high stiffness, high hardness, good wear resistance and good corrosion resistance. Manufacturing Methods Alumina is manufactured through the Bayer process in which bauxite is purified. The product is usually in multiple phases rather than singly corundum. Thus, the production process can be optimized to manufacture a tailored product. The pore structure and solubility of aluminum depends on the phases present. Alumina ceramics can then be manufactured in a wide range of purities with other additives designed to improve properties. There are also a wide variety of methods used to process ceramic material, including machining and shape-forming to produce different sizes and shapes of components. Alumina ceramics can also be joined to other ceramics or metals using brazing and metallizing techniques. 3. Composite Materials - Carbon fiber composites Carbon fibers are largely composed of carbon atoms are about 5-10 micrometers. These materials are made from the precursor – organic polymers characterized by strings of molecules held together by atoms of carbon. Carbon fiber reinforced composite materials find applications in the manufacture of aircraft and spacecraft components, automobile springs, car bodies, bicycle frames, and many other parts where the designer prefers high weight-to-strength ratio. Structure of Carbon fiber Carbon fiber has an atomic structure similar to that of graphite – consisting of carbon atoms that are arranged in a regular hexagonal pattern, although there is a difference in the way graphite sheets interlock. The sheets in graphite are arranged in parallel and in a regular fashion to form a crystalline material. The intermolecular forces that hold the graphite sheets together are weak van-der Waals forces, giving the material its soft and brittle properties. Carbon fiber may have graphitic or turbostratic, or a hybrid structure combining both turbostratic and graphitic parts depending on the precursor used in making the fiber. In turbostratic structure, carbon atom sheets are crumbled together. These type of carbon fibers are derived from polyacrylinitrile, while those with graphitic structure are derived from mesophase pitch. Figure 4: A cross-section of carbon fiber showing the atomic structure of carbon atoms arranged in a plane. Properties and characteristics of polymer materials Carbon fiber composites have technical properties suitable for a wide range of applications. They include: High strength-to-weight ratio Good thermal and electrical conductivity High tensile strength Low density – light Excellent fatigue resistance Low thermal expansion High corrosion resistance Good fire resistance Self-lubricating Excellent electromagnetic interference shielding property Manufacture of Carbon fiber Production of carbon fibers is partly a chemical process and partly a mechanical process. The production process involves bonding together carbon atoms in crystals and aligning them parallel to the fiber axis. Alignment of the crystals gives the fiber its characteristic high strength-to-volume ratio. Several carbon fibers can be bundled together, forming a tow. To form a composite material, carbon fibers are usually combined with other materials such as plastic resin. When combined with this material and wound, it produces carbon-fiber-reinforced polymer – an extremely rigid and brittle material. Another material that is combined with carbon fibers is graphite – which forms carbon-carbon composites with very high thermal resistance. A variety of liquids and gases are used during the manufacturing process to achieve a specific effect as they react with the fiber, or to prevent some reactions with the fiber. A typical sequence of operations involved in manufacturing of carbon fiber from polyacrylonitrile are: spinning, stabilizing, carbonizing, treating the surface and sizing. 4. Polymer Materials - Polycarbonate/ABS Polycarbonate (PC)/ABS (acrylnitrile-butadiene-styrene) polymer material is a blend of the two materials to provide a unique thermoplastic alloy that combines excellent properties of PC with high processability of ABS. The high heat distortion of the resulting PC/ABS polymer is an improvement compared to ABS, and the low temperature impact resistance is an improvement over PC. Thus, the balance of properties in the PC/ABS is largely controlled by the ratio of ABS and PC in the blend, the PC molecular weight and the added package. The ratio of ABS and PC mainly affects the heat resistance properties of the final product. A blend of PC and ABS exhibit a synergic effect, producing a polymer with excellent impact resistance better than that of ABS or PC alone at very low temperatures. Structure of PC/ABS Polymer The morphology of the blend depends on the viscosity ratio of the individual polymers and the additives used, shear conditions, and the interfacial tension between the blend partners. TEM image (see figure 5) of the PC/ABS blend show a morphology of the blend collected from a compounded pellets. The blend is characterized by varying degree of deformation and orientation of PC and ABS. ABS forms is observed to form the matrix, while PC forms a dispersed phase. Figure 5: PC/ABS structure Properties of PC/ABS Polymer High heat resistance High impact strength at very low temperatures Easy processing High stiffness High dimensional stability and low shrinkage Excellent anti-ionizing radiation Manufacturing of PC/ABS Polymer Manufacture of PC/ABS polymer is mainly by the addition of foreign substance, known as additives, to the PC/ABS blend. This is done in order to achieve desired properties required for material application. The additives added typically include: filler materials, stabilizers, plasticizers, flame retardants and colorants. A variety of components are produced via injection molding of equipment and computer housing. The blended thermoplastic improves the processability of PC by lowering the melt viscousity and improving shear thinning behavour. It also lowers the heat distortion of ABS. Task 4: Work in a group to carry out mechanical tests on a selection of materials. You are the required to in around 1000 words produce, a full illustrative description of each of the tests and process your results/data and present them in a suitable form. The tests to be carried out are to include the following. a. Hounsfield tensile test Description of the test Some of the mechanical properties of a material can be determined by performing a simple tensile test. Hounsfield tensometer is an equipment used to perform a tensile test to determining the ultimate tensile strength of a material. Ultimate tensile strength is the highest stress a material can withstand just before it breaks (Agrawal, 1988). The test can also be used to determine a material’s yield strength. In this test, we measured the tensile test of the following: 0.2% Carbon Steel normalised at 910oC; 0.4% Carbon Steel normalize; 0.54% Carbon fibre normalize; and, 0.54% Carbon Steel oil quenched at 880oC and tempered at 550oC Procedure for Hounsfield tensile test Before beginning the test, the maximum load that could be applied to the specimen was calculated, having made a sensible assumption of the ultimate tensile strength of the specimen material. Practically, the ultimate tensile strength is normally higher than the values published in the literature. This is for the reason that the data published in the literature is a “guaranteed” value or the lowest one will ever obtain in real life. First, the measurements of the specimen were taken, ascertaining the specimen as accurate as possible for length and diameter. The specimen was then mounted into the Hounsfield tensometer, taking care of all slack. A sufficient initial load of about 75% of yield strength (100-200N) was then applied on the specimen to ensure that the specimen fully fitted in the jaws of the Hounsfield tensometer. The tensometer force, extension and auxiliary are then set at zero before the test began. The load was recorded on the Hounsfield Logger Programme as the test proceeded with increasing outputs of force and extension, until at a point when the specimen broke. The specimen was then removed and elongation measured and recorded, while the tensile test data saved to excel. This data was used to prepare Load-extension Plots. Results The results of the tensile test are presented in Table 1 below: Table 1: Tensile test results Sample Diameter, Ø Elongation percentage Reduction percentage DN, 0.4% Carbon Steel Normalize 5.04 mm 25% 55% C, 0.2% Carbon Steel Normalize 6.40 mm 40% 70% E, 0.54% Carbon Fibre Normalize 5.06 mm 15% 55% K, 0.54% Carbon Steel OQ@ 880°C T@550°C 3.57 mm 8% 45% ***OQ = Oil Quenched ***T = Tempered Figure 6: Load-extension plot for 0.2% Carbon steel normalize Maximum load = 6315N Area = 3.22 x 10-5 m2 Ultimate Tensile Strength = Maximum Load/Area UTS = = 196.1MPa Figure 7: Load-extension plot for 0.54% Carbon Steel normalize Maximum load = 8677N Area = 1.0 x 10-5 m2 UTS = = 867.7MPa Figure 8: Load-extension plot for 0.4% Carbon Steel Maximum load = 9904N Area = 2.0 x 10-5 m2 UTS = = 495.2MPa Figure 9: Load-extension plot for 0.54% Carbon Fiber Maximum load = 5545N Area = 2.01 x 10-5 m2 UTS = = 275.9MPa In this experiment, it is seen that the amount of carbon present in the metal influences the material’s mechanical properties, specifically, the tensile strength. Increasing the carbon content in steel improves properties such as hardenability, strength and hardness. Carbon steel with 0.54% carbon achieves the highest ultimate tensile strength (867.7MPa), followed by Carbon steel with 0.40% carbon (495.2MPa) and the least is carbon steel with 0.2% carbon with ultimate tensile strength of 196.1MPa. However, the material with 0.54% carbon fibre is stronger than carbon steel with 0.2% carbon, with ultimate tensile strength of 275.9MPa. The presence of carbon in the steel modifies the crystal structure of the material, hence improving its mechanical properties (Calika, Duzgunb, Sahinc, & Ucard, 2010). b. Jonomy end quench test Description of the test This test measures hardenability of steels. Hardenability refers to the measure of the capacity of the material to be hardened to a particular depth after quenching it from its austenitizing temperature. Given that the rate of cooling reduces further away from the quenched end, the effects of different cooling rates from rapid water cooling to air cooling towards the other end can be measured. Determining this property is important in selection of the best combination of alloy steel and thermal treatment to reduce distortion and thermal stresses when producing various components from the material. Testing Procedure First, a cylindrical sample specimen of steel measuring 100mm length, 25mm diameter was obtained. The specimen was then normalized to eliminate irregularity in microstructure brought by previous forging and then austenitised at temperatures of 800-900oC. The specimen was then transferred to the test machine, secured vertically and sprayed with water on one end in a controlled manner. This simulates quenching of a steel component in water. After quenching, the specimen was ground along its length to a depth of 0.38mm to get rid of decarburized material. Finally, the hardness was measured at 0.75 mm intervals, starting from the quenched end. Task 5: Using data sources including your test results from task 4, published BS/EN standards for steels and data tables sourced from text books or steel manufacturers guidance, assess the quality of the data obtained and apply this information to suggest a suitable ferrous material which could be heat treated and used as a steel support pin which requires a hardness value of HRC32 and a ultimate tensile strength in the range of 850 – 1000 N/mm2. Table 2: Comparison of experimental values and theoretical values of mechanical properties of carbon steel. Sample Diameter, Ø Elongation percentage Reduction percentage UTS (MPa) Experimental Theoretical Experimental Theoretical Experimental Theoretical DN, 0.4% Carbon Steel Normalize 5.04 mm 25% 25% 55% 50% 495.2 620 C, 0.2% Carbon Steel Normalize 6.40 mm 40% 15.0% 70% 40% 196.1 440 E, 0.54% Carbon Fibre Normalize 5.06 mm 15% 20% 55% 55% 275.9 350 K, 0.54% Carbon Steel OQ@ 880°C T@550°C 3.57 mm 8% 10% 45% 35% 867.7 800 From the data presented in table 2, there is a close comparison between the mechanical properties obtained through lab experiment and those documented in the literature. This validates the data obtained experimentally. Heat treatment of carbon steel is aimed at improving mechanical properties of the material, such as hardness, ductility, impact strength and yield strength. The ultimate tensile strength of the required material is in the range of 850-1000 Pa. All the materials tested surpass this strength. However, the 0.2% carbon steel can be heat-treated through the following processes: normalizing (at 890°C – 940°C), forging (at 1150°C – 1280°C), tempering ( at 150°C – 200°C), annealing (at 870°C – 910°C), and stress relieving (at 500°C – 700°C) (AZoM, 2012). This will process a suitable material for the required steel chain pins. Conclusion Today, a wide range of materials and manufacturing processes exist, and the major challenge is the task of choosing the best material while keeping the cost of manufacturing at minimum. Overcoming such a challenge needs a better understanding of material properties and processes as well as the manufacturing technologies associated with these materials. Reference Read More

The cost of the material should be appropriate and have multiple sourcing options to cope with competition in the market. This will ensure that once the manufacturing design and technologies have been laid out, it will be economical to continue producing the product in the long run. 3. Processing and manufacturing In selecting a material, one has to consider how the product will be made. Manufacturing properties such as machinability, casting, welding, ease of joining, formability etc. should come into consideration.

Having the right material manufacturing properties will ensure that the product becomes technically producible. For example, manufacturing a forged component will require a material with excellent flowability to be able to forge it without cracking. 4. Environmental factors Environmental factors to consider in the selection of a material include: i. The effect of the component on the environment; ii. The effect that the service environment will have on the component; and iii. The effect of manufacturing processing on the environment.

One of the most important concerns in the automotive industry are reduction of emissions, protection of resources, and recycling. Thus, the aspect of component recycling should also be taken into account as part of environmental considerations. Countries in the European Union and Asia have issued environmental regulations on automobile end-of-life requirements. The process of selecting materials is a complex interaction between the factors discussed above. For example, the cost will be influenced by how difficult it will be to source and process the material, and the effect a material will have on the environment will depend on its properties.

Therefore, if a novel material is to be used for a component, it has to be selected at the design stage, so that the design process is done using the right material properties. The baseline is that engineers involved in the selection process should have a thorough understanding of material properties and processing characteristics. A clear definition of the function of a component to be manufactured should be provided in order to identify the most ideal properties. Consideration of the manufacturing process is essential in attaining a process that is capable of making the desired component shape, with the right accuracy, and at an appropriate cost.

In real life, both material selection and processing are considered simultaneously for the reason that not all materials will be compatible with existing processes. For instance, titanium, nickel and steel cannot be die-casted, conventional techniques cannot be used to machine ceramic materials. The complexity of shape may further limit the choice of a given process. Task 2: Research and identify some of the different materials that are used in the manufacture of modern motor vehicles. For each material identified you should state the component, where it is on the motor vehicle, the primary material selection criteria, and into which of the groups below it fits. I. Metallic Materials a) Metals used in making the engine and gear box Metals used to make automotive engine and gear box are cast iron, graphite cast iron, aluminum alloys, and Carbon steel and steel alloys.

Cast iron – These metals are used to build the engine block – the main housing many engine parts. The primary selection criteria of these materials is their durability, strength and resistance to wear and low weight. These increases power and efficiency of the engine. Steel and steel alloys– These are typically used in building crankshafts. Their selection is based on a combination of the most desirable properties such as strength, durability and wear resistance. High performance crankshafts are also built using nickel-chrome alloy because of its fatigue properties and very high strength, coupled with good impact resistance and ductility at high strengths.

Compacted graphite cast iron – This metals are used in making connecting rods and engine block, especially where low weight is a major concern.

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