Notion of Engineering Materials - Assignment Example

Engineering Materials Task 1: Changes in properties and behaviour of metals Recrystallization refers to the process in metals that is achieved through heating whereby new sets of grains nucleate and grow to the extent of entirely consuming the original deformed grains (JOHN, 1991). Recrystallization has various effects on different metals as discussed below: In steel, recrystallization results to an increased tensile strength as well as ductility as the annealing temperatures increases. On the other hand, quality casts are produced from Aluminium at the temperature range of between 700oC to 750oC. Cold working usually affects the following properties in metals: tensile strength, ductility, hardness and yield strength. Therefore, cold working affects these properties in both aluminium and steel. Effects of alloying of aluminium differ from one metal to another. For instance, chromium alloys usually gives stainless steel their resistance to corrosion. Other alloying metals increases ductility decreases work hardening and improves the metals formability. The processing temperatures of polymers like nylon and acrylic can make the polymers to darken or turn to a yellow colour. On the same note, pressure usually affects the compressibility as well as the expansion of polymers improves the mechanical properties of the polymers (JOHN, 1991). Moulding pressure usually affects the mechanical orientation of polymers. As moulding pressure is increased with time, the polymers are curved into the required shape. Examples of such kind of polymers include vulcanized rubber and unsaturated polyester resins. Curing temperature may have a stress effect on the polymer during the curing if the process takes a longer time than required (ASHBY & JONES, 1999). The level of water in the clay used for making ceramics will determine the durability of the pottery and other ceramic products. Sintering force helps in compacting together the particles resulting to strongly make ceramic products including cups and plates. Firing temperature usually helps in expelling water that is trapped between the clay particles. Firing of clay usually improves its texture by making it hard and impervious. Ductile reinforcement supplies fracture toughness to the polymer matrix through the act of pulling out or through plastic deformation. The metal reinforcements that are not in a toughened condition, there might be more toughening to be attained when the fibres remain in the matrix and plastically deform nature instead of pulling out (ASHBY & JONES, 1999). They are thus said to be havingthe unused plastic potential. When they bridge a given crack; their nature that is characterized by plastic deformation leads to the sharp rise in the force that tries to pull out such afibre. Delamationtends to affect the buckling load and the ultimate response of cylindrical composite shells that is subjected to externally pressurized loadings, depending upon the initial length and location of the ply orientation, laminate curvature, as well as delamination.  Particle dispersion in cermet comprises of a composite material than contains some particles which are used in bonding other particles. The application of force, temperature variations, or even the high electric effects in most of the engineering materials such as steel and Aluminium can either lead to effects of ductility, fatigue, creep, or even the brittle nature. Ductility is regarded as a resultant feature due to application of excessive pressure or force to a given metal with the ultimate ability of deforming permanently before fracture. Brittle nature refers to the kind of fracture involving little or no permanent kind of deformation. On the other hand, fatigue refers to an element that has to do with the ultimate weakening of a given material component due to repeated application of loads (ASHBY & JONES, 1999). Finally, creep refers to the tendency of a given solid substance to deform permanently or move slowly under the ultimate influence of a mechanical stress. It usually occurs due to the long-term contact to the high stress levels that operate below the material’s yield strength Task 2: Engineering materials that could be used for the blade of the wind turbine: The wind turbines are often utilized in the conversion of the kinetic energy of wind into an electric form. The wind energy designs can either for the single or grouped turbines. There have been a constant change with regards to the wind turbines development, but the main feature has been on its blades. This is because of the fact that, the blades usually plays the pivotal role of capturing and setting wind in a sequential and constant motion (ASHBY & JONES, 1999).They are primarily made up of either reinforced plastic, wood epoxy, or even glass but can at times be made up of steel or aluminium The modern turbines are commonly comprised of three blades. The major variation normally occurs when it comes to the aspects of rotor the ultimate diameter. There are various materials that can be used for the development of the wind turbine blade. The main forms of materials have are what are referred to as the Gurit materials. The primary point for taking these materials into consideration that; it is encompassed of the products that tend to cover all the current production approaches that includes Resin infusion, wet lamination, and the prepreg (JOHN, 1991). The advent of bigger blades as well as the increasing Safety and Health awareness, various blades are currently manufactured either through the prepreg process or resin infusion, and thus, whilst Gurit manufactures the wet laminating resins, the developmental focus has remained on the infusion and prepreg technology and all the associated products. The basic materials for the Infusion Blades: The main basic components materials that are mostly utilized in the infusion blades are the infusion resin, dry fabrics, structural adhesive, as well as the core material. The entire manufacture of either the fibre conversion or the fibre itself is not applicable at all in this perspective (OHRING, 1995).The three remaining material categories happen to be the main areas of proficiency for these essential materials whereby the considerable developmental task has always been focused towards the provision of a product range extreme quality. The categories include those with infusion with resin, and infusion with prime, among others. The Infusion Resin The ultimate deciding on whether the suitability of the resin system the infusion process needs careful thoughts towards various aspects regarding the production process. These mainly include the ambient conditions, component size, reinforcement, mechanical and thermal properties, as well as the blade certification (ASHBY & JONES, 1999). There should also be the aspect of putting into consideration the future elements with regards to optimizing the production process, mould utilization as well as the cycle time. To attain this kind of strong infusion resin that is responsible for offering a range of velocities that can be mutually tailored towards a continuous improvement processes is significant. Infusing with prime Resin: This kind of infusion Resin has, on the other hand, been encompassed with a reduced viscosity of resin as well as longer working hours. It has thus made it to be ideal for infusion of larger segments with complicated reinforcements in a single operation. It is comprised of a low exothermic feature that tends to allow for the production of thicker segments without the premature gelation risks that usually occur due to the subjected heat. The lower exothermic reaction also assists in extension of the tool lives due to the thermal cycle reduction. This material has since achieved excellent physical and mechanical feature from a moderate temperature of around 50°C post cure, thereby offering the finished laminate properties lying between low-temperature and hand lamination cure prepreg (TIMINGS, 1998). It is available with various hardeners that offer a wide range of cure speeds and working times that provides a versatility of manufacturing a number of components. 8 (a) The most appropriate engineering materials that should be used for the car body: There are various engineering materials that are often utilized in the manufacture of various cars, but the main basis is normally on the aspects of its prevailing characteristics and objectives. For instance; the decrease of the carbon dioxide emissions as well as the consequential requirement for the lightweight design remains as the dominant driver for the contemporary car body material models (OHRING, 1995).The quality of a vehicle with regards to the design, look-and-feel, safety, as well as the driving features should not be merely taken into dire consideration. The processes within the entire production chain should simply be increasingly flexible and efficient, while the entire quality materials have to be available globally. The launch of the vehicle body material concepts and the realistic ideologies for their ultimate future must be at the ultimate focus to a greater extent. All the leading global networks of the automobile engineers should be reviewed critically reviewed in a practical nature. The car bodies have to be both economically and technologically viable for various vehicle segments. This is simply because this concept is of great value to the safety as well as the age of the car bodies (OHRING, 1995). b. The criteria you used when coming to a decision about which material to choose: There are various criterions that can be duly utilized while deciding on the best materials that should be used for building a car body. The main metal components that can be put into focus are the steel and the Aluminium components. For instance; in a steel component, the new applications that are constantly viable for the high to the ultrahigh strength alloys should be considered. On the other hand, the emerging possibilities that exist for the utilized hot-formed steel parts should be through the tailored tempering process (COMMITTEE ON ENGINEERING MATERIALS, 1958). In addition, the level of corrosion protection with regards to such segments should be highly optimized in one way or the other. The other main property that should be considered should be is on the aspect whereby the tailored blanks and many other semi-finished goods are utilized in a very innovative design. For Aluminium, the mechanical strengths that are practically reachable should be based on the hot-formed characteristics (TIMINGS, 1998). On the other hand, the possibilities that tend to exist for the innovative semi-finished goods should be analysed. The other major segment is that; the conditions that can be arrived at through further operational integration in the die-cast parts have to be considered. Finally, the main thing amongst all these properties is on the material’s availability. 9. Reasons for the steel and Aluminium selection: From the above analysis, there are various reasons that are often taken into dire consideration while selecting a given engineering material. The main element has often been on the entire quality as well as the sustainability. They should be comprised of a low exothermic feature that tends to allow for the production of thicker segments without the premature various mechanical mishaps that can occur due to the subjected heat. The lower exothermic reaction also assists in extension of the tool lives due to the thermal cycle reduction. Such kind of materials can achieve excellent physical and mechanical features from a moderate temperature of around 50°C, thereby offering the finished laminate properties lying between low-temperature and hand lamination (JOHN, 1991). They are thus available with various hardeners that offer a wide range of cure speeds and working times that provides a versatility of manufacturing a number of components. In various steel components, the new applications that are have been championed for are constantly viable for the high to the ultrahigh strength alloys. On the other hand, the emerging possibilities that exist for the utilized hot-formed steel parts have been through the tailored tempering process. In addition, the level of corrosion protection with regards to such segments should be highly optimized in one way or the other. The other main thing that leads into selection of such materials is often on the aspect whereby the tailored blanks and many other semi-finished goods can be utilized in a very innovative design. On the other hand, the possibilities that tend to exist for the innovative semi-finished goods should be analysed. The other major segment is that; the conditions that can be arrived at through further operational integration in the die-cast parts have to be considered. So, all these among many features should be the reason for the ultimate selection and consideration of a give engineering material (COMMITTEE ON ENGINEERING MATERIALS, 1958). Reference List: ASHBY, M. F., & JONES, D. R. H. (1999). Engineering materials 2 an introduction to microstructures, processing, and design. Oxford, Butterworth-Heinemann. http://search.ebscohost.com/login.aspx?direct=true&scope=site&db=nlebk&db=nlabk&AN=240202. COMMITTEE ON ENGINEERING MATERIALS. (1958). Engineering materials. New York, Pitman Pub. Corp. JOHN, V. (1991). Engineering materials. Basingstoke, Macmillan. TIMINGS, R. L. (1998). Engineering materials. OHRING, M. (1995). Engineering materials science. San Diego, Academic Press. http://site.ebrary.com/id/10206031. Read More