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GATE 2021 MT – Question 57

Mechanical Behaviour of Materials · Dislocations and strengthening · 2 marks · Numerical answer

A shear stress 100 MPa bows a dislocation between precipitates spaced 0.2 μm. If spacing increases to 0.5 μm, the needed shear stress is ______ MPa (nearest integer).

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Show answer and explanation

Correct answer: 40 to 40

Explanation

For unchanged shear modulus and Burgers vector, the Orowan bowing stress is inversely proportional to obstacle spacing.

Thus τ2=100×0.2/0.5=**40 MPa**.