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GATE 2020 MT – Question 18

Mechanical Behaviour of Materials · Plasticity and yield criteria · 1 mark · Multiple choice

One requirement for a material to exhibit superplasticity is

  1. Coarse-grained microstructure
  2. High strain-rate sensitivity
  3. Low strain-hardening exponent
  4. High elastic modulus

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Show answer and explanation

Correct answer: (B) High strain-rate sensitivity

Explanation

High strain-rate sensitivity means a locally faster-deforming region requires appreciably higher flow stress, which opposes localization and necking. It therefore permits very large uniform elongation. Fine stable grains and an appropriate temperature/rate range are also typical, whereas coarse grains and high elastic modulus are not the defining listed requirements. Select B.

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