Engineering Material: Ductile, Brittle, Fatigue, Creep - Assignment Example

a) Ductile fracture Ductile fracture 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. The main property here is simply the material’s ability to deform, which may either lead or fail to end up in fracture based on the applied magnitude of the force (International Conference on Civil Engineering and Material Engineering & In Zhang et.al, 2012). The ductility’s property is somewhat directly related to that of toughness, even though the latter is often measured in presence various stress concentrations. However, the ultimate ability of absorbing energy, as well as the subsequent deformation before any form of fracture is the basic feature of both toughness and ductility. b) Brittle Fracture Brittle fracture refers to the kind of fracture involving little or no permanent kind of deformation. Various non-metals often lack ductility and are thus subject to the brittle fracture. The good examples of such materials are chalk, bricks, rock, and even glass. It generally revolves around the entire properties of very strong, hard, and notch-sensitive metallic elements that are prone to brittle (Murphy, 1957). It is conversely true that the weaker and softer metals often have ductile behaviours. The only exception is the Gray cast iron. This kind of metal is brittle in nature because it is comprised of large number of the internal graphite flakes acting as the main internal stress concentrations, thereby limiting the metal’s ability to either deform or flow, which is thus essential for the ductile behaviour. c) Fatigue Fatigue refers to an element that has to do with the ultimate weakening of a given material component due to repeated application of loads. It can generally be termed as the continuous and restricted structural deformation that that happens when a specific material is exposed to a constant cyclic loading. The maximum stress units that lead to such a damage might be extremely below the material’s strength that is normally regarded as the yield stress limit, or critical tensile stress limit (Murphy, 1957). If the subjected loads are beyond a particular threshold, various microscopic cracks eventually starts forming at the ultimate stress concentrators including the surface, grain interfaces, as well as the persistent slip bands. The crack shall eventually reach a vital size whereby it will suddenly propagate into the consequent fracture. d) Creep Creep or cold flow often 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 (Murphy, 1957). It is more rigorous in the materials that are exposed to massive heat for longer periods of time. Ultrasonic Testing (UT) The entire utilization of ultrasonic oscillations to detect various flaws in diverse materials has turn out to be a standard test methodology that sets basis on the measurements with ultimate regards towards all the significant influential factors. Nowadays, there is a greater expectation that the perspective of ultrasonic testing as supported by enormous technological advancements gives out reproducible test outcomes within very narrow tolerances (Polakowski & Ripling, 1966). It assumes the exact knowledge of most influencing factors as well as the ability of applying this methodology in the testing technology. The Ultrasonic noise detectors are often used to identify various changes in gearboxes, bearings, as well as the rotating machinery because of changes in load and wear. Task 2 Process of degradation associated with each of metals, polymers and ceramics: The polymer degradation is often the aspect of transformation in the material’s properties; ranging from the tensile strength, shape, and colour, among others. It usually occurs when there is under influence of various environmental elements including heat, chemicals, or light such as alkalis, salts, and acids. These kinds of changes are normally undesirable, since they bare characterized with chemical disintegration and cracking of products. The ultimate changes in such properties are usually regarding as aging (Polakowski & Ripling, 1966). Such a change is usually delayed or prevented in furnished products. Degradation can hence be significant for reusing/ recycling the polymer waste in order to reduce or prevent the environmental pollution. It can, on the other hand, be deliberately induced so as to help in structure determination. Various polymers can hence be degraded through photolysis in order to give room for lower molecular weight. The electromagnetic waves that are encompassed with the visible light’s energy such as the ultraviolet light, X-rays as well as the gamma rays are often involved in those reactions. Task 3 How one destructive and one non-destructive test procedure produces useful results: In destructive testing, the tests are often undertaken to the failure of the specimen, so as to understand its material behaviour or structural performance under various loads. Such kinds of tests are normally much easier to perform, since they tend to yield a lot of information, and are often much easier to understand as compared to non-destructive testing. It is thus most appropriate, and economical for the mass-produced objects, since the entire cost of destroying smaller number of the given specimens is usually negligible. Non-destructive testing (NDT), on the other hand, refers to a wide cluster of the analysis methodologies that are often utilized in industry and science for evaluating the material’s properties, systems, or component, without causing any form of damage. As much as NDT do not alter permanently the inspected particle, it is a valuable technique that tends to save both time and money in product troubleshooting, evaluation, and research (Polakowski & Ripling, 1966). It is utilized in various settings that cover a broad range of the industrial activity because of the continuous development of the new NDT applications and methods. The non-destructive testing techniques are normally applied in various industries whereby a component’s failure would cause critical hazards mainly in transportation, building structures, pressure vessels, piping, as well as hoisting equipment. Task 4 How radiation affect the behaviour of engineering materials: Radiation usually impacts on various devices and materials in a number deleterious ways. For instance; it leads a given materials into becoming radioactive in nature, primary through the perspective of neutron activation, or due to the presence of very high-energy gamma radiation through photodisintegration. The other perspective can be through the aspect of the nuclear transmutation of various elements within a specific material, for example, the Helium and Hydrogen production, which can sequentially change the material’s mechanical properties, thereby causing embrittlement and swelling (National Academy of Engineering & National Academies, 2004). In addition to this, radiation effects can also manifest in various engineering materials through the aspect of radiolysis, which is responsible for the entire weakening of these materials. It hence leads to swelling, polymerization, corrosion, belittlements, cracking, as well as the ultimate change in its desirable optical, electronic properties, or mechanical properties. Furthermore, it tends to form reactive compounds, thus affecting various other materials such as the aspect of ozone cracking. Finally, radiation is largely responsible for the element of ionization that causes the electrical breakdowns specifically in the semiconductors that are employed in various electronic components with the consequent currents introducing the operational mistakes or even the permanent damage of such devices. The only solution that can counteract with these massive effects is the aspect of developing materials that are mutually intended for the high radiation environments including the additional atmospheric and the nuclear industry applications, is the aspect of making them to be radiation hard in order resist such cognitive impacts through material selection, design, as well as the fabrication methodologies. Task 5 How Oxidation affect the behaviour of engineering materials: The Oxidation effect on the engineering materials usually occurs through the perspective that is primarily regarding as corrosion. Corrosion refers to deterioration a given material due to its interaction with the entire surroundings. It is largely regarded as a natural phenomenon. For instance; when newly manufactured steel is exposed to the air, the original shiny surface shall definitely be coated with rust within a shortest time period. The metal’s tendency to corrode is largely related to the lower stability with regards to the metallic nature. The metals usually occur either in the zero oxidation state, pure metallic state, or in form of other elementary compounds (National Academy of Engineering & National Academies, 2004). In the natural world, most metals are found as compounds with other elements, thereby indicating greater stability regarding their oxidized nature. So, to acquire a pure metal from such a compound, energy input happens to be one of the main necessities. On the other hand, the reverse is true since various materials tend to release their stored energies through corrosion when exposed to the entire environment. It is hence an equivalence to what normally happens when there suspension of a given object above the ground. When given room for falling or reaching a stable nature, it typically returns to the ultimate position of minimum energy on ground. It is thus similar to the entire metal's oxidized state. The various chemical reactions taking place more often in the corrosion processes are termed as the redox reactions. These kinds of reactions require the oxidized material species, and as well as the oxidizing agents. The complete reactions can thus be sub-divided into oxidation and reduction reactions. The metal often tends to lose electrons when it comes to the aspect of oxidation. This kind of action usually occurs at the anode. On the other hand, the oxidizing agent usually gains the entire electrons that have been mutually shed by a consequent metal when it comes to the aspect of reduction reaction. It occurs in a zone that is regarded as the cathode. The impact of the high pressure oxidation on mechanical properties such as tensile, creep, and low cycle fatigue of the normalized ferritic steel after the ultimate anneal has been approximated to be about 23°C to 550°C. It has been found out that both the oxidation and micro structural changes affect the alloy’s mechanical properties. The tensile test results shows that the un-oxidized alloy has high strength as compared to its reported literary value. The alloy’s oxygen content of up to 0.06 percentage weight of oxygen reduces its strength to a considerable extent but is affected marginally by further oxidation increase (National Academy of Engineering & National Academies, 2004).The alloy’s ductility also increases, while the low cycle fatigue reduces, and the creep resistance feature improves with the enhanced oxidation time. The creep and fatigue behaviours have been constantly ascribed because of temperature effects, internal oxidation, as well as cycling. TASK 6: Brinell hardness Test: The Brinell’s hardness test is one of the oldest test methodologies that are still in common contemporary use. It is often utilized in determination of the hardness with regards to castings or forgings that have got course grain structures for the Vickers or Rockwell testing. Through variation of the ball size and test force, all the given metals can nearly be tested by use of a Brinell test. The values are considered as being test force independent provided that the test force/ ball size relationship is equal. Brinell testing the US is normally done on steel and iron castings using the 3000 kilograms test force, with a 5mm radius carbide ball. The Aluminium and various other soft alloys are tested frequently by use of a 500Kg test force. In Europe, it is done using a wide range of ball sizes and forces. Here, it is usually common to perform these tests on smaller parts by use of a 1 millimetre carbide ball, with a test force of around 1kg (International Conference on Advanced Material Research & In Fan, 2012). All the Brinell tests utilize the carbide ball indenter as the main apparatus. It thus involves a number of test procedures. First and for most, the indenter tends to be pressed into a given sample by a precisely controlled test force. That force is thus maintained for a particular dwell time of approximately 10 to 15 seconds. After the completion of such a dwell time, the indenters are removed leaving behind the indent in the sample. The indent’s size is therefore optically determined through the measurement of two round indent diagonals using a portable microscope. The Brinell’s hardness value is a force function regarding the test force that is substantially divided by the indent’s curved surface area. The ultimate indentation is considered as being spherical with the radius that equals half the ball’s diameter. The two diagonal’s average is thus used in calculating the Brinell hardness using the formula stated below: The Brinell number that usually ranges from HB 750 to HB 50 for various metals tends to increase with increase in the sample’s hardness. For instance; in the resultant figure that is stated as 356HBW, 356 show the computed hardness level while W indicates the fact that a carbide ball was entirely used. References International Conference on Civil Engineering and Material Engineering, In Zhang, H., In Jin, D., & In Zhao, X. J. (2012). Advanced research on civil engineering and material engineering: Selected, peer reviewed papers from the 2012 International Conference on Civil Engineering and Material Engineering (CEME 2012), August 25-26, Wuhan, China. Durnten-Zurich, Switzerland: Trans Tech Publications. International Conference on Advanced Material Research, & In Fan, W. (2012). Advanced materials research II: Selected, peer reviewed papers from the 2012 2nd International Conference on Advanced Material Research (ICAMR 2012), January 7-8, 2012, Chengdu, China. Durnten-Zurich, Switzerland: Trans Tech Publications. Murphy, G. (1957). Properties of engineering materials. Scranton: International Textbook Co. National Academy of Engineering., & National Academies (U.S.). (2004). Emerging technologies and ethical issues in engineering: Papers from a workshop, October 14-15, 2003. Washington, D.C: National Academies Press. Polakowski, N. H., & Ripling, E. J. (1966). Strength and structure of engineering materials. Englewood Cliffs, N.J: Prentice-Hall. Read More