1.1 Microstructures
When metals are in solid form they are crystalline. The crystal structure of a metal refers to the internal structure or arrangement of atoms in an ordered, repeating or three dimensional patterns. Normal metallic objects contain a collection of very small crystals which makes them polycrystalline. These crystals are grains. Casting is an example of a metallic object which has large grains that can be resolved with the naked eye and these structures are referred to as macrostructures (Copper Development Association Inc, 2013).
Typically the grains of a metal object are very small and cannot be viewed by the naked eye. An optical microscope or an electron microscope are used to observe the structural features of the small grains at magnifications greater than 100 times. Structures requiring this range of magnification are called microstructures (Copper Development Association Inc, 2013).
Figure 1 Microstructure of Aluminium Titanate
The structure is the most important aspect of an engineering material. The structure of a material is related to its composition, performance, properties and processing history. Therefore the microstructure of a material provides information linking its composition and processing to its properties and performance. Physical metallurgy is the science provides an explanation of the microstructures, through what is happening inside a metal during the various processes. Metallography is the science of preparing the specimens, examining them under a microscope and interpreting the microstructures (Copper Development Association Inc, 2013).
Microstructural analysis is used to gain information on how the material was produced and the quality of the resulting ma...
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...s an effect on the temperature and method of cooling. Annealing is used to remove the effect of solution heat treatment so that machining or working qualities can be improved (Properties Identification and heat treatment of metals)
1.4.2 Solution heat treatment
Solution heat treatment involves heating an alloy to a specific temperature fo r a specific length of time so the alloying elements go into solid solution and form a single phase. The final properties of the alloy can be affected by the soaking temperature and time and the cooling rate. Soaking temperature relies on the various phases within the alloys, each one of these phases will dissolve in solid solution at different rates. The soaking time is based on the rate of dissolution of alloying elements into solid solution and the conditions which the alloy was cast. (Coimbatore, Tamil Nadu, 2001)
3D printing is primarily for rapid part prototyping and small-run production in a variety of industries. In the meantime, the term additive manufacturing has come to represent the use of 3D printing to create metallic components and final parts, differentiating from conventional subtractive manufacturing processes. 3D printing uses computer-generated designs to create build paths that reproduce a digital model through consolidation of materials with an energy source. The process typically uses a laser, a binder or an electron beam that solidifies material as it is directed along scanned over a pre-placed layer or the build path of material. This method has been used successfully with metals, polymers and ceramics. Metals are still in their infancy in terms of finished part production. Metallic parts produced with 3D printing frequently require additio...
We use metals to construct all kinds of structures, from bridges to skyscrapers to elevators. The strength as well as durability of materials that are crafted out of metal make the materials ideal not only for construction but also for many other applications.
Thompson, A., Peteraf, M., Gamble, J., Strickland III, A. J., & Jain, A. K. (2008). Crafting &
shape is like crystal cubes. This lead ore has a significant source of silver and the majority of
Metal finishing is the critical part and step in preparing the metal for painting. It happens between the bumping stage when the metal is pried, hammered, pulled, and pushed into shape and the filling stage, when the small defects and details in metal finished surfaces are filled before being painted. Any type of finish is applied over your work weather the it be solvent, powder coated, or plastic it will have an index of reflection and ...
Construct a model of methane using a tetrahedral center (4 prongs) and four rods of the same color to show how the 4 H's are attached.
The high temperature application of Austenitic Stainless Steel is somewhat limited because at higher temperatures it undergoes a phenomenon called Sensitization. According to Ghosh et al. [1], it refers to the precipitation of carbides and nitrides at the grain boundaries. Precipitation of Chromium rich carbides (Cr23C6) and nitrides at the grain boundaries result when the Austenitic stainless steel is heated and held in the temperature range of 500-8500C (773K-1123K). This precipitation of carbides taking place at the grain boundary is because of their insolubility at these temperature ranges. This leads to Chromium depreciated regions around the grain boundaries. So the change in microstructure is takes place and the regions with low Chromium contents become susceptible to Intergranular Corrosion (IGC) and Intergranular Stress Corrosion Cracking (Alvarez et al.) [1, 2]. Along with carbides and nitrides there is formation of chi phase. The chi phase, which is a stable intermetallic compound, consists of Fe, Cr, and Mo of type M18C. Some studies reveal that sensitization may lead to formation of Martensite. In addition to the altered microstructure, mechanical properties of the Austenitic Stain...
The electron microscope has become one of the most widely utilized instruments for materials characterization. An electron microscope is a scientific instrument that allows us to “see” objects so small that they cannot be seen in any other way. (CITE) Electron microscopes have allowed scientists to see individual molecules and atoms for the first time.
The basis for the understanding of the heat treatment of steels is the Fe-C phase diagram. Because it is well explained in earlier volumes of Metals Handbook and in many elementary textbooks, the stable iron-graphite diagram and the metastable Fe-Fe3 C diagram. The stable condition usually takes a very long time to develop, especially in the low-temperature and low-carbon range, and therefore the metastable diagram is of more interest. The Fe-C diagram shows which phases are to be expected at equilibrium for different combinations of carbon concentration and temperature. We distinguish at the low-carbon and ferrite, which can at most dissolve 0.028 wt% C at 727 oC and austenite which can dissolve 2.11 wt% C at 1148 oC. At the carbon-rich side we find cementite. Of less interest, except for highly alloyed steels, is the d-ferrite existing at the highest temperatures. Between the single-phase fields are found regions with mixtures of two phases, such as ferrite + cementite, austenite + cementite, and ferrite + austenite. At the highest temperatures, the liquid phase field can be found and below this are the two phase fields liquid + austenite, liquid + cementite, and liquid + d-ferrite. In heat treating of steels the liquid phase is always avoided. Some important boundaries at single-phase fields have been given special names. These include: the carbon content at which the minimum austenite temperature is attained is called the eutectoid carbon content. The ferrite-cementite phase mixture of this composition formed during cooling has a characteristic appearance and is called pearlite and can be treated as a microstructural entity or microconstituent. It is an aggregate of alternating ferrite and cementite particles dispersed with a ferrite matrix after extended holding close to A1. The Fe-C diagram is of experimental origin. The knowledge of the thermodynamic principles and modern thermodynamic data now permits very accurate calculations of this diagram.
To investigate the temperature change in a displacement reaction between Copper Sulphate Solution and Zinc Powder
Figure 1: Image of the nanoscale, this illustration shows how small things at the nanoscale really are (nano.gov, 2013).
Solids are more stable than liquids and gases. One type of solid is a Crystalline solid. The particles in a crystalline solid have a regular repeating pattern. The types of crystalline solids are metals, alloys, salts, valence crystals, molecular crystals, polymers, and plastics.
In chemistry, metals compose a great number of the periodic table elements. Each metal has its own characteristic mass,
Toughness is the ability of a metal to mutilate plastically and to absorb energy in the process before it breaks or fracture. Metals can be heat treated to alter the properties of strength, ductility, toughness, hardness or resistance to corrosion. This can be done by using heat treatment processes which include precipitation strengthening, quenching, annealing and tempering. Annealing and tempering are the most prominent methods for treating metals. A material may become more or less brittle, harder or softer, or stronger or weaker, depending on the treatment used.