Microstructures

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Grain Boundary Migration - Continued
In-situ deformation of Octachloropropane, C3Cl8

Click image to enlarge

44. 1st. stage of post-deformation recovery - After 33 minutes at room temperature, octachloro-propane grains still contain deformation bands, but their grain boundaries have been highly mobile. The large yellow grain at upper center, and the small white one on it's right side, are good examples of extreme suturing of grain boundaries. Small grains at base of image have fully recovered and recrystallized by this process of grain boundary migration, and there has been considerable grain growth in this area as a result.

FOV 0.8mm, Nicols Crossed.

45. 2nd. stage of post-deformation recovery - After 33 minutes at room temperature, the specimen was held for three seconds over a hot plate, with the result that many grain boundaries have become extremely lobate. The elongation of grains, so apparent in previous images, is lost as the grains become more equant in response to grain boundary surface energy restraints. This type of recrystallization, in the presence of heat but after all stress is removed, is called annealing recrystallization. Deformation bands are still present, but fewer in number.

FOV 0.8mm, Nicols Crossed.

46. 3rd. and final stage of post-deformation recovery - After another 40 minutes at room temperature, the material starts to resemble the starting morphology of image #40. Grain boundaries have straightened out and grains are more equant than in the previous image. Note that some grains have grown at the expense of their neighbors. There are still isolated deformation bands and the range of grain size remains large, as is typical for annealing recrystallization in many rocks.

FOV 0.8mm, Nicols Crossed.

Grain Boundary Migration - Continued In-situ deformation of Octachloropropane, C3Cl8	Click image to enlarge
44. 1st. stage of post-deformation recovery - After 33 minutes at room temperature, octachloro-propane grains still contain deformation bands, but their grain boundaries have been highly mobile. The large yellow grain at upper center, and the small white one on it's right side, are good examples of extreme suturing of grain boundaries. Small grains at base of image have fully recovered and recrystallized by this process of grain boundary migration, and there has been considerable grain growth in this area as a result. FOV 0.8mm, Nicols Crossed.
45. 2nd. stage of post-deformation recovery - After 33 minutes at room temperature, the specimen was held for three seconds over a hot plate, with the result that many grain boundaries have become extremely lobate. The elongation of grains, so apparent in previous images, is lost as the grains become more equant in response to grain boundary surface energy restraints. This type of recrystallization, in the presence of heat but after all stress is removed, is called annealing recrystallization. Deformation bands are still present, but fewer in number. FOV 0.8mm, Nicols Crossed.
46. 3rd. and final stage of post-deformation recovery - After another 40 minutes at room temperature, the material starts to resemble the starting morphology of image #40. Grain boundaries have straightened out and grains are more equant than in the previous image. Note that some grains have grown at the expense of their neighbors. There are still isolated deformation bands and the range of grain size remains large, as is typical for annealing recrystallization in many rocks. FOV 0.8mm, Nicols Crossed.