GATE 2022 MT – Question 50
Consider a tilt boundary of misorientation of 2୭in an aluminium grain. The lattice parameter of aluminium is 0.143 nm. The spacing between the dislocations that form the tilt boundary is ____________ nm (round off to 2 decimal places).
Practise this question in The GATE Grind →
Show answer and explanation
Correct answer: 2.86 to 2.93
Explanation
An FCC perfect dislocation has $b=a/\sqrt2=0.143/\sqrt2$ nm. At small tilt angle, $D\approx b/\theta$ with $\theta=2\pi/180$ radians.
Thus $D=2.8967$ nm, rounding to **2.90 nm** using the supplied lattice parameter.