Photomicrographs |
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This is a 50-50 alloy of lead and bismuth which shows primary Pb-rich epsilon phase (photo left) with both continuous precipitation of white bismuth along the edges of the epsilon and discontinuous (or cellular) precipitates in the centers. The right side of the photo is eutectic with "Chinese script" structure. Scale bar is 50 micrometers long. |
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Plain carbon steel, furnace cooled, with microconstituients pearlite (lamellar structure) and ferrite (white grains). Ferrite grains are formed above 727 degrees C. Pearlite is formed from the eutectoidal breakdown of single phase austinite into two phases, cementite and ferrite at 727 degrees C. Scale bar is 50 micrometers long. |
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Alloy steel, heat treated at 850 Degrees C, then water quenched to produce the very hard phase called martensite. Scale bar is 50 micrometers long. |
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An incomplete weld of a bike frame which failed. Apparent in the image is the bright weld material in the center, the surrounding lighter heat affected zone (HAZ), and dark outer unaffected base metal. Field of view is approximately 15 mm. |
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This image is 60-40 lead-tin solder showing the dark dendrites of primary lead surrounded by Pb-Sn eutectic. Scale bar is 667 micrometers. |
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Shown at left is a higher magnification of solder showing varying structure of the Pb within the two phase Pb-Sn eutectic, which surrounds the primary lead dendrites. Scale bar is 100 micrometers long. |
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Photomicrographs by Ruth I. Schultz Kramer |