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Study of Optical Metallurgical Microscope Pdf Study of optical metallurgical microscope pdf Continue INDIAN INSTITUTE OF TECHNOLOGY KANPUR Division of Materials and Metallurgical Engineering Virtual Laboratories for Thermal Processing and Materials Characteristics Experiment 1 Microstructure Observation in Light-Optical Microscope Targets Of this laboratory is (i) familiarized with the functioning of the metallurgical microscope, and (ii) observe and interpret the microstructures of these samples. The theory of the microscope function is to turn an object into an image that usually increases to varying degrees. There are many complex techniques (such as electron microscopy) available to perform this transformation. However, the principles involved are just like those developed for light microscopes as far back as 4 centuries ago. The basic concept of any visualization system can be understood from the point of view of a light-optical microscope. The simplest optical microscope is a single convex lens or magnifying lens. There are two important classes of optical microscopes: the type of transmission and the type of reflection of microscopes. Optical mechanisms for these two classes of microscopes are shown in drawings 1.1a and 1.1b. The same two types occur in electron microscopy, which leads to the transmission of electron microscopy and scanning electron microscopy. An integral part of the optical microscope is the lighting system, which consists of a light source and a capacitor lens. The purpose of the capacitor is to focus the diverging beam of light from the source on a small portion of the sample (object A) studied. Most light microscopes use a two- lens system: the lens lens and the eyepiece (often referred to as the projector lens). The target lens forms an intermediate image of B, which is further enlarged by the eyepiece. The use of objective lenses of different focal lengths alters the increase in these microscopes. Conventional zooms are usually 50X, 100X, 200X, 250X, 500X and 1000X. 35mm camera locations for imaging and/or CCD (charged connected device) camera for digitizing images that can be stored in a computer are very common accessories in modern light microscopes. Figure 1.1: Optical beam diagram for a) transmitted lighting and (b) reflects illumination. The performance of any microscope can be understood from the point of view of two important parameters: resolution and depth of field. Resolution is simply defined as the nearest distance between two points, which is clearly visible through the microscope as two separate entities. Resolution (r) is given by the equation proposed by Lord Reilly: (1.1) where, l light wavelength, M is a refractive environment index between the object (sample) and the target lens, and the semi-angle subtended (see figure 1.2a). The term msina is also known as numerical diaphragm. Using the equation (1.1), the best resolution that can theoretically be obtained is in the range of 150 to 200 nm. However, the various aberrations in the lenses will make this resolution degrade. The depth of field is defined as the range of positions of an object (sample) for which the eye does not detect any change in the sharpness of the image (see figure 1.2b). Depth of sharpness (h) is given: (1.2) The depth of field is in the light microscope of about 1 mm. Thus, the depth of field is very small, and therefore to obtain sharp images must be taken during the preparation of the sample. The surface of the sample should be very flat and horizontal. Figure 1.2: Definition (a) of the half-corner, subordinated to the objective aperture, and b) the depth of field h. The samples commonly used in material science and engineering are opaque, and therefore the optical microscope used has a reflective type (discussed above). Figure 1.3 shows clearly marked sketches of a typical commercial optical microscope. It can be noted that objective lenses installed on the rotating nasal element make it easy to change the objective lenses of different magnifyings. The stage at which the sample is placed can be moved to the xy (horizontal plane). A 35mm camera or CCD camera can be mounted on a vertical tube at the top (see digits 1.3) to photograph microstructures. The methodology now establish a remote connection to the optical microscope. Once you've connected, you'll see a live image of the microscope. The process of launching a computer program and monitoring microstructures is given here. Save and transfer microstructural images to your local computer. The results and discussion examine the various functions available on the metallurgical (or reflective type) of the microscope. The main functions of immediate interest are concentration, change of zoom and stage movement. (i) The increase changes by rotating the rotating nasal element (see figure 1.3) to lead to targets of different focal length and/or numerical aperture. Focus is achieved by using coarse and thin focus pens to adjust the distance between the target and the sample. It is important to ensure that the lens does not fall to the surface of the sample during the focus at a higher magnification, where the lens lens comes very close to the surface of the sample). It is good practice to start focusing in strides, starting with the lowest goal increase. (iii) The observation area on the sample can be altered with x and y stage handles, usually below the stage (see figure 1.3). The microstructures of the observed samples are below: (i) plain carbon steel compositions: 0.2 wt%C (hypoeutectoid steel), 0.8-whe cent C (euthectoid steel) and 1.2 t-C (hyperetecoid steel). (ii) Cast iron: white cast iron, grey cast-iron and spherized graphite (SG) iron. (iii) Cu-40wt%'n For each sample, do the following: (i) Watch the microstructures on different increases and sample areas. Notice the target's numerical aperture. Observed microstructures can display many artifacts (i.e. functions that are not part of the structure). The most frequently observed artifacts are etch-pits (pits produced on the surface during etching) and scratches (produced during polishing). It is easy to recognize etch-pits by the fact that both microstructural elements (such as grains and grain boundaries) and etch-pits do not appear in sharp focus at the same time. By using good methods of sampling, these artifacts can be minimized. For each sample, identify the phases observed in microstructures. (iv) I don't observe and draw the main features of each microstructure. The sketch microstructure should represent a typical structure, not a copy of any particular area. Clearly identify the various elements in the sketch microstructures. Relates observed microstructures to those expected in the phase chart (see digits 1.4). (a) (b) Figure 1.4: (a) Fe-Fe3C and b) Cu-n. The findings list the main findings of this experiment. Issues, although a much larger increase can be obtained in a light-optical microscope, the vast majority of light microscopes are commercially available limited to about a 1000X increase. Why? If sunlight is used as a light source (as it used to be in old microscopes) rather than an electric lamp, then that will affect the image quality. Explain. What is the difference in monitoring the microstructure with the purpose of different numerical holes, but the same increase? Although it is impossible to focus on both microstructural elements and etch-pits in a light microscope at the same time, both of these functions appear in sharp focus together in a scanning electron microscope. Why? Check here for the microscope and related goal of Fast FTPS on Planet Go FTP FREE software microscope that uses visible light Modern optical microscope with mercury lamp for fluorescence microscopes. The microscope has a digital that's connected to a computer. An optical microscope, also called a light microscope, is a type of microscope that typically uses visible light and a lens system to create enlarged images of small objects. Optical microscopes are the oldest microscope design and may have been invented in their current composite form in the 17th century. Basic optical microscopes can be very simple, although many complex designs aim to improve the resolution and contrast of samples. The object is placed on the scene and can be directly viewed through one or two eyepieces on the microscope. In high power microscopes, both eyepieces usually show the same image, but with a stereo microscope, slightly different images are used to create a 3-D effect. The camera is usually used to capture an image (micrograph). The sample can be illuminated in a variety of ways. Transparent objects can be illuminated from below and solid objects can be illuminated by light coming through (bright field) or around the (dark field) lens. Polarized light can be used to determine the crystalline orientation of metal objects. Phase-contrast imaging can be used to increase the contrast of images by highlighting small details of different refractive indexes. A range of objective lenses with varying magnifying glass are usually provided, allowing them to rotate into place and providing the ability to scale. The maximum power increase of optical microscopes is usually limited to about 1000x due to the limited allowing power of visible light. The increase in the compound of the optical microscope is the product of an increase in the eyepiece (say, 10x) and lens target (say, 100x) to give an overall increase of 1000×. Modified environments such as oil or ultraviolet light can increase the increase. Alternatives to optical microscopy that do not use visible light include scanning electron microscopy and transmitting electron microscopy and scanning the probe's microscopy and, as a result, can achieve a much larger increase. The Types of Diagram is simply a microscope There are two main types of optical microscopes: simple microscopes and composite microscopes.
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