Virtual Labs

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

Twinning in crystals can cause which of the following effects on the SADP in TEM?

a: Twinning does not affect the SADP. Explanation

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b: Twinning can result in double diffraction spots. Explanation

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c: Twinning leads to ring patterns. Explanation

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d: Twinning causes the diffraction spots to shift in position. Explanation

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How does the presence of amorphous regions in a crystalline material affect the SADP observed in TEM?

a: It causes the diffraction spots to become sharper. Explanation

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b: It leads to the appearance of a halo or diffuse ring. Explanation

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c: It enhances the intensity of the diffraction spots. Explanation

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d: It does not affect the SADP at all. Explanation

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Cold rolling reduces grain size due to which mechanism?

a: Dynamic recrystallization Explanation

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b: Grain boundary migration Explanation

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c: Mechanical twinning and dislocation interaction Explanation

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d: Electron beam irradiation Explanation

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In a heavily cold-rolled FCC metal like copper, what happens to the diffraction spots in the SADP?

a: They become broader and more diffuse due to increased defect density Explanation

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b: They remain sharp and well-defined Explanation

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c: They disappear completely Explanation

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d: They transform into concentric rings 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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