Virtual Labs

Observation and interpretation of defect structure in cold rolled aluminium, copper and zinc

The distance between diffraction spots in a SADP is inversely related to:

a: The wavelength of the incident electron beam Explanation

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b: The atomic number of the elements in the sample Explanation

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c: The real-space lattice spacing of the crystal Explanation

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d: The aperture size used in the TEM Explanation

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What does the presence of concentric rings in a SADP indicate?

a: A single crystalline structure Explanation

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b: An amorphous material Explanation

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c: A polycrystalline material Explanation

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d: A non-crystalline structure Explanation

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Which of the following statements is true about the effect of dislocations on TEM SADP?

a: Dislocations lead to the broadening of diffraction spots. Explanation

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b: Dislocations result in the formation of ring patterns. Explanation

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c: Dislocations do not affect the SADP. Explanation

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d: Dislocations cause spot splitting in the SADP. Explanation

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Which factor influences the extent of defect formation in cold-rolled metals?

a: Rolling temperature Explanation

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b: Rolling speed Explanation

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c: Initial grain size Explanation

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d: All of the above Explanation

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What is a common effect of severe cold rolling on the electrical conductivity of copper?

a: Increases due to reduced impurity content Explanation

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b: Decreases due to increased defect density and electron scattering Explanation

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c: Remains unchanged Explanation

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d: Increases due to twin boundary formation Explanation

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A dislocation has Burgers vector b = (a/2)[110] and is imaged using diffraction vector g = 1̅11, what is expected?

a: Strong contrast Explanation

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b: No contrast Explanation

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c: Twin contrast Explanation

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d: Stacking-fault contrast Explanation

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Why does WBDF provide higher defect resolution than conventional DF imaging?

a: It increases specimen thickness. Explanation

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b: It suppresses strain contrast. Explanation

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c: It enhances sensitivity to local lattice distortions. Explanation

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d: It removes diffraction effects. Explanation

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