Match the phenomena in Column I with the typical observations in Column II.
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In materials science, understanding phenomena like dynamic strain aging, recrystallization, and superplasticity is crucial for interpreting stress-strain curves and the behavior of materials under stress. These phenomena are associated with distinct features like serrations, dislocation density reduction, and grain boundary sliding.
Let’s analyze each phenomenon and its corresponding observation:
- P. Dynamic strain aging: This phenomenon is characterized by the appearance of serrations in the stress-strain curve due to the interaction between dislocations and solute atoms at higher temperatures. Thus, P corresponds to 4. Serrations in stress-strain curve.
- Q. Recrystallization: Recrystallization involves the formation of new, dislocation-free grains which leads to a decrease in dislocation density. Therefore, Q corresponds to 3. Decrease in dislocation density.
- R. Bauschinger effect: The Bauschinger effect is observed when there is a decrease in yield stress with a reversal of loading direction, meaning the material becomes weaker in the opposite direction. Hence, R corresponds to 2. Decrease in yield stress with a reversal of loading direction.
- S. Superplasticity: Superplasticity involves grain boundary sliding at elevated temperatures and high strain rates, where the material undergoes extensive deformation without failure. Thus, S corresponds to 1. Grain boundary sliding.
Therefore, the correct matching is:
- P – 4: Dynamic strain aging with serrations in the stress-strain curve
- Q – 3: Recrystallization with decrease in dislocation density
- R – 2: Bauschinger effect with decrease in yield stress with a reversal of loading direction
- S – 1: Superplasticity with grain boundary sliding
