...what happens in USA, corrosion of metals costs the economy almost $300 billion per year at current prices, which translates to 3-4% of GDP. Besides the economic concern, corrosion may adversely affect the environment. Worse than all those mentioned, corrosion can cause unexpected death from corrosion-related accidents. For example, the sudden collapse caused by corrosion fatigue of the Silver Bridge over the Ohio River in 1967 cost 46 lives on top of the needless-to-say millions of dollars material loss. Therefore, the benefits brought about by corrosion are outweighed by its detriments. The fact is, about 33% of these costs could be diminished by using corrosion-resistant materials. Being defined as the sideways displacement of material from its original position on a solid surface performed by the action of another surface, wear is another mechanical property of materials that materials scientists consider when selecting materials in a design task. In order to be wear-resistant, a material must be hard and strong. The demand for corrosion- and wear- resistant coatings is nowadays rapidly increasing, especially in oil and gas industries. The most common solutions are Hard Cr and Quench-Polish-Quench (QPQ) processes. However, these two processes affect the environment adversely. As alternatives, coating layers can be introduced to metal samples. Coatings can be done with or without electricity. If electricity is involved, the process is called electroplating. It is done by immersing...
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...Drew Kelly IET 307 HW5 Dr. Nair 1) 2) 3) 4) I speculate that the type of corrosion was called Hydrogen Embrittlement. Various metal alloys, specifically some steels, experience a reduction in ductility and tensile strength when atomic hydrogen penetrates into the material. Basically it is a type of failure, the brittle fracture occurs as the cracks grow and rapidly propagate. HE is very similar to stress corrosion in that a normally ductile metal is exposed to a stress and a corrosive atmosphere. For HE to occur some source of Hydrogen has to be present and also there must be a possibility of formation of its atomic species. High strength steels are very susceptible to HE and increasing the materials strength tends to enhance the chance the material can become HE. This form seems to fit the applied situation. 5) Yes it is possible to have reinforced steel bars that can corrode while still inside the concrete. Another perfect example of this is, as mentioned in the above answer, is Hydrogen Embrittlement. Again He is when a hydrogen atom gets inside the material and causes it to corrode, a good way to prevent the chances of corrosion are to add in inhibitors. Inhibitors are substances that when added at low concentrations that can prevent corrosion. Another way you can prevent corrosion is called Cathodic Protection. This is when you apply an external source, electrons to the metal, making it a cathode. Then the action of corroding is put in...
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...TALLER N° 2 1. El papel aluminio que se usa para almacenar alimentos pesa unos 0.3g por pulgada cuadrada. ¿Cuántos átomos de aluminio contiene una pulgada cuadrada de ese papel? Masa aluminio: 0.3 g Peso atómico: 26.98 g/mol n° moles= 0.3/26.98 = 0.011 moles n° átomos= (0.011*6.023x10^23) = 6.697x10^21 átomos Rta: una pulgada cuadrada de ese papel aluminio contiene 6.69x10^21 átomos 2. Calcule la cantidad de átomos de hierro en una tonelada corta (2000lb) de hierro. Masa de hierro: 2000 lb= 907184,74 g Peso atómico Fe:55,845 g/mol n° moles= 907184,74/55,845 = 16244,69 moles n° átomos= (16244,69*6,023x10^23) = 9,7842x10^27 átomos Rta: una tonelada corta de hierro tiene 9,7842x10^27 átomos 3. Para niquelar una parte de acero de 200in², de superficie, con una capa de 0.002in de espesor de níquel: ¿Cuántos átomos de Níquel se requieren? ¿Cuántos moles de Níquel se requieren? Volumen: 0,4 in³ =6,55 cm³ ρNi: 8,9 g/cm³ peso atómico Ni: 58,69 g/mol Gramos de Ni= 6,55 cm³*8,9 g/cm³ = 58,295 g n° moles= 58,295/58,69 = 0,9933 moles n° átomos= (0,9933*6,023x10^23) = 5,9825x10^23 átomos Rta: se requieren 5,9825x10^23 átomos y 0,9933 moles 4. Un alambre de Oro tiene 0.70mm de diámetro y 8.0cm de largo, la densidad del Oro es 19.3g/cm³. ¿Cuántos átomos contiene este alambre? Peso atómico Au: 196,96 g/mol ρAu= 19,3 g/cm³ V= s*h S= (0,035)²*(3,1416)= 3,8485x10^-3 cm² v= 3,8485x10^-3*(8) = 0,03079 cm³ Gramos de Au = 19,3*0,0379 =0,5942 g n° moles=...
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...Fall 13 rev. 1 Engineering & Green Technology Department Fall River, Massachusetts Course Number & Title: Instructor: EGR172 - Material Science Prof. Sid Martin Phone #: 774-473-7934 Email: sidmartin007@gmail.com (preferred) Sidney.Martin@bristolcc.edu Engineering Materials Properties & Selection, Budinski & Budinski, Ninth Edition, Prentice Hall Lecture: Monday & Wednesday @ 11-12:15 pm, Rm: B112 Lab: Monday or Wednesday @ 12:30-1:45 pm, Rm: B112/B113 Text: Class Times & Locations: I. Course Description: A study of the physical, mechanical and chemical properties of engineering materials. Particular emphasis is placed on the interdependency of atomic structure, micro-structure, material phase relationships, and solid state reactions to each other and to the modification of these properties. The use of metals, plastics and advanced materials in economic, sustainable and reliable design is investigated. The laboratory includes metallographic examination using light microscopy and the study of material science principals and treatments of metals. II. Course Requirements: The Student is required to review daily assignments and lecture notes, and complete assigned reading, laboratory presentations and homework problems. Two hours of out of class study per class/laboratory hour should allow students to be adequately prepared for class and complete these requirements. Homework and Laboratory Presentations will follow a prescribed format and should be neat and organized...
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...properties of injected plastic parts in presence of cracks, a tension test and a constant load. The material used was Polystyrene and the surface-active substances were olive oil and corporal sweat. This study was conducted because it was observed that the surface-active substances affects the mechanical properties of the resin as well as the presence of cracks, and actually is not reported any methodology for conducting this study. Experimental Part For this study, there were injected 110.5*85.5*1 mm plates in a REED-Prentice 100 TE (Clamp Force = 100 ton) injection machine with an injection mold with two similar cavities, but with a different located entrance. The used material was a Polystyrene PS-2820 from Estirenos del Zulia (Table 1). In table 2 are showed the used optimal process conditions. Notches were mechanized in each plate with a saw. The normalized tensile test specimens were cut with a milling machine. It was used a Galdabini 2500 universal test machine to make mechanical tests, and a Starrett Sigma VB300 stereoscopic magnifying glass to verify the crack length. To study the crack surface it was used a Macro Magnifying glass Olympus SZ61. To study the orientation and the stress concentrator in the plaques it was used a polaryscope Photoelastic Inc. 082. Introduction Since long time ago, the fracture has been a serious problem for the use of all materials. The fracture may be described how any change of the...
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...Received: 14 February 2012 / Accepted: 22 October 2012 # Springer Science+Business Media Dordrecht 2012 Abstract The study presents the effect that elastomeric matrices different in their chemical nature (a non-polar and crystallizing natural rubber and a polar and non-crystallizing acrylonitrile-butadiene rubber) have upon the dynamic mechanical and dielectric properties of the composites comprising different amounts of conductive carbon black. Dynamic mechanical thermal analysis (DMTA) and Dielectric thermal analysis (DETA) are the techniques used for studying the structure-properties relationships of the composites. The experimental results show that the matrices studied and their specific properties have a great impact O. A. Al-Hartomy : A. A. Al-Ghamdi Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia O. A. Al-Hartomy Department of Physics, Faculty of Science, University of Tabuk, Tabuk 71491, Saudi Arabia F. Al-Solamy Department of Mathematics, Faculty of Science, University of Tabuk, Tabuk 71491, Saudi Arabia F. Al-Solamy Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia N. Dishovsky (*) : M. Mihaylov : M. Ivanov Department of Polymer Engineering, University of Chemical Technology and Metallurgy, 8 Kl. Ohridski Blvd., 1756, Sofia, Bulgaria e-mail: dishov@uctm.edu F. El-Tantawy Department of Physics, Faculty of Science, Suez Canal University, Ismailia, Egypt upon both the dynamic...
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...powdered material by electrical discharge. This discharge results from energizing the sample by a momentary pulse of large electric current. One can summarize the sequential effects of this electrical pulse in five key steps: (1) spark plasma is generated (2) the sample is “plasma heated” (3) the sample is “joule heated”, (4) the particles fuse into a compact, solid object by electrical field diffusion, and (5) the material undergoes plastic deformation to further densify the powder. In many cases, this method of sintering produces objects with superior mechanical properties to conventionally sintered objects. Furthermore, it produces highly dense objects in a shorter time period and at a lower temperature. With spark plasma sintering, ceramics can be sintered in minutes, as compared to hours and days using conventional processes. This emerging technology presents the opportunity to manufacture materials more cost-effectively. II. Introduction Within the umbrella of materials science and engineering lies the processing of various classes of materials, including metal alloys, composites, polymers, and ceramics. According to the Ceramic Tile Institute of America, a ceramic is an inorganic, nonmetallic solid processed via the action of heat and subsequent cooling.3 Among the wide variety of these inorganic, nonmetallic materials used in commercially viable applications, a common characteristic is high melting point, due to the nature of these materials themselves---they...
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...Experiment 5 - Cold Work, Recovery, Recrystallization and Grain Growth Objective To study the effects of cold working on the microstructure and mechanical properties of 70/30 Cartridge Brass. Background A small percentage of the energy expended in plastically deforming a material remains stored in the metal as an increase in internal energy. Changes are produced in both its physical and mechanical properties. Principally, there is a marked increase in hardness and electrical resistivity with the amount of cold working. Microstructurally, this increment in internal energy is associated with an increase in the dislocation density as well as the density of point defects, such as vacancies and interstitials. For most metals, the dislocation density increases from the values of 106-107 lines/cm2 (typical of the annealed state) to 108-109 after a few percent deformation and up to 1011 -1012 lines/cm2 after heavy deformation. At a more macrostructural level, the grains become markedly elongated in the direction of working and heavily distorted. This distortion is evident from a bending of annealing twins and from unevenness in etching caused by local strain inhomogeneities. While the increased hardness and strength that result from the working operation can be important, it is often necessary to return the metal to its initial condition by annealing. This usually means holding the cold worked metal at a temperature above about 1/3 of the absolute melting point for a period of time. The...
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...The Effect of Curing Time on The Properties of Fly Ash-based Geopolymer Bricks W. I. Wan Mastura1,a, H. Kamarudin1,b, I. Khairul Nizar2,c, A.M. Mustafa Al Bakri 1,d, H. Mohammed3,e 1 Center of Excellence Geopolymer and Green Technology, School of Material Engineering, Universiti Malaysia Perlis (UniMAP), P. O. Box 77, d/a Pejabat, Pos Besar, 01007 Kangar, Perlis, Malaysia. 2School of Environmental Engineering, Universiti Malaysia Perlis (UniMAP), P. O. Box 77, d/a Pejabat, Pos Besar, 01007 Kangar, Perlis, Malaysia. 3 King Abdul Aziz City Science & Technology (KACST), P.O. Box 6086, Riyadh 11442, Kingdom of Saudi Arabia awanmastura89@gmail.com, bvc@unimap.edu.my, cnizar@unimap.edu.my, dmustafa_albakri@unimap.edu.my, ebnhusain@kacst.edu.sa Keywords: Geopolymer, Fly ash, Bricks, Geopolymerization, Compressive strength Abstract. This paper reports the results of an experimental work conducted to investigate the effect of curing conditions on the properties of fly ash-based geopolymer bricks prepared by using fly ash as base material and combination of sodium hydroxide and sodium silicate as alkaline activator. The experiments were conducted by varying the curing time in the range of 1-24 hours respectively. The specimens cured for a period of 24 hours have presented the highest compressive strength for all ratio of fly ash to sand. For increasing curing time improve compressive strength and decreasing water absorption. Introduction A geopolymer,...
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...squeezed. The amount of strain introduced determines the hardness and other material properties of the finished product. The advantages of cold rolling are good dimensional accuracy and surface finish. Cold rolled sheet can be produced in various conditions such as skin-rolled, quarter hard, half hard, full hard depending on how much cold work has been performed. This cold working (hardness) is often called temper, although this has nothing to do withheat treatment temper. In skin rolling, the metal is reduced by 0.5 to 1% and results in a surface that is smooth and the yield point phenomenon--excessive stretching and wrinkling in subsequent operations, is eliminated. This makes the metal more ductile for further forming and stretching operations. Quarter Hard, Half Hard, Full Hard stock have higher amounts of reduction, upto 50%. This increases the yield point; grain orientation and material properties assume different properties along the grain orientation. However, while the yield point increases, ductility decreases. Quarter Hard material can be bent (perpendicular to the direction of rolling) on itself without fracturing. Half hard material can be bent 90º; full hard can be bent 45º. Thus, these materials can be used for in applications involving great amounts of bending and deformation, without fracturing. Annealing, in metallurgy and materials science, is a heat treatment wherein a material is altered, causing changes in its properties such as strength and hardness...
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...MATS1101 Materials Strand/MATS9520 INTRODUCTION TO MATERIALS ENGINEERING Dislocations Ashby & Jones, Volume 1, Chapter 9 Ideal Strength of Materials Last week we saw that the slope of the interatomic force-distance curve at equilibrium spacing is proportional to Young's Modulus, E. Interatomic forces become negligible for r > 2r0. F ~2Fmax Fmax Attraction 0 Repulsion r0 2r0 r0 r0 ~1.25r0 2r0 r Figure 8 Interatomic force-distance curve The maximum in the force-distance curve occurs at ~1.25r0, (where F = Fmax). If applied stress is greater than Fmax per bond, bonds between atoms are broken and fracture occurs. Ideal strength, , corresponds to bond rupture at Fmax. Calculation of ideal strength: Slope E 0.25r0 r0 2r0 r0 Figure 9 Ideal Strength ~ From the force-distance curve, where r = 1.25r0, = 0.25 and 2 is ideal strength). Copyright School of Materials Science and Engineering, UNSW, 2012. E ~ 2 0.25 ~ E 8 ~ E 15 E 15 A better estimate using interatomic potential gives Glasses and some ceramics have a yield strength of For other ceramics and polymers, For metals, y y 10 1 E 15 E 15 y 10 1 10 5 Actual vs Ideal Strength 10-1 10-2 10-3 Cement (nonreinforced Ceramics Silica glass Diamond Soda glass SiC Al2O3, Si3N4 MgO, ice Alkali halides Metals Polymers Low density PE Epoxies PP, PMMA High density PE Nylons...
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...Advanced materials. Global industry analysis. The material science has evolved over the centuries and rapidly grown during last hundred years. Today we are talking about advanced material industry as a top point of material science evolution. The science of advanced materials enters to all spheres of human being from clothing and household items to the space industry. Also this industry widely presented in following spheres: bioscience, electronics, medical and healthcare, construction, automobile, power and alternative energy, manufacturing, sport, telecommunication and many others. Indeed industry of advanced materials will be one of the biggest drivers of the world economy growth in current century. “Materials” is matter of everything physical like glass, ceramics, polymer, metal alloys. And “Advanced materials” are materials with higher performance characteristics “such as toughness, hardness, durability and elasticity, ability to memories shape or sense changes in the environment and respond.” Advanced materials can be implanted into usual items we are using in everyday life. This is something we have never thought about like apparel which people are wearing could become more insulated when you feel cold or touch screen computer which you can wrap and fold with very high performance and less energy use. Market for advanced materials is unlimited because each “traditional material” in every item can be improved and switched to advanced material use. It...
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...Altan, P. Sartkulvanich, N. Kardes The Center for Precision Forming (CPF), The Ohio State University, Columbus, Ohio, USA Abstract The demand for application for lightweight materials such as Ultra/Advanced High Strength Steels (U/AHSS), aluminum alloys, magnesium alloys and boron steels in automotive industry is increasing to reduce vehicle weight and increase crash performance. The use of these relatively new materials requires advanced and reliable techniques to a) obtain data on material properties and flow stress, b) predicting springback and fracture in bending and flanging, c) selecting lubricants and die materials/coatings for stamping and forging and d) designing tools for blanking and shearing. In addition, designing the process and tooling for a) hot stamping of boron steels, b) warm forming of Al and Mg alloys, and c) optimizing the use of servo-drive presses require advanced Finite Element based simulation methods. CPF is conducting R&D in most of these topics and also in many hot and cold forging related topics. This paper gives an overview of this research and discusses how the research results are applied in cooperation with industry. Keywords: Metal Forming, Sheet metal, Forging, FEM 1 INTRODUCTION The Center for Precision Forming (CPF) has been established with funding from the National Science Foundation (NSF) and a number of companies (www.cpforming.org). CPF is an outgrowth of the Engineering Research Center for Net Shape Manufacturing (ERC/NSM – www.ercnsm.org)...
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...properties of the materials J. Michalski ) , J. Marszalek, K. Kubiak Faculty of Mechanic Engineering and Aeronautics, Rzeszow UniÕersity of Technology, 35-959 Rzeszow, ul. W. Pola 2, Poland ´ ´ Received 9 August 1999; received in revised form 17 February 2000; accepted 17 February 2000 Abstract The main objective of this paper is to study and experimentally quantify the cam and follower wear mechanisms of a diesel direct valve-gear. Camshafts are made of nodular cast iron, surface hardened, ion nitrided and nitrosulphurized, and those made of grey chilled cast iron are mated with followers made of chilled grey cast iron and hardened steel. The investigation was carried out on a laboratory bench equipped with an engine head with a camshaft, followers and systems creating the conditions necessary for a routine run of the valve gear. Cam wear was defined by comparing the profile lifts of the cams. The height of the followers was measured using a coordinative measuring machine and a perpendicular optimeter. The rotational speed, valve displacement and the torque required by the valve gear were measured. Camshaft C9 and the thimble shaped followers with regulating plates F6 were also examined in a diesel engine. The effects of the materials the kinematic pair was made of, heat treatment and thermochemical treatment, the cams’ own stresses at the moment-of-friction value, as well as the extent and nature of element wear, were analysed. q 2000 Elsevier Science S.A. All rights ...
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...questions which will be answered, centered on material studies. The first question is based around work hardening, the changes in the atomic structure as a result thereof and the reason why some materials are more susceptible to work hardening than others. The second question is based on the process of embrittlement, as well as listing a few different ways in which embrittlement can occur. The third and last question is based on the significance of heat affected zones, with special emphasis on the effects with regards to steel. Work hardening Work hardening is a phenomenon found in metallic materials, where deformations in the metals have led to the metal itself becoming strengthened, or harder as such. The deformations which cause this effect are called plastic deformations, which means that the metal material was stressed beyond the point where elastic deformation takes place, thereby resulting in a permanent deformation in the crystalline structure of the metal material. These plastic deformations are caused by high heat exposure for a specific minimum length of time, causing the molecules within the crystalline structure to rearrange themselves. A few common physical processes which take place on metals and can cause this effect are as follows: hammering, bending, rolling, drawing, shearing, squeezing or collisions between metals for example. All of the above would result in some form of work hardening in metallic materials susceptible to it, due to the fact that large...
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