Answer to Question #288962 in Mechanical Engineering for Peace

Question

Calculate the volume percentage change as iron transform from FCC to BCC if the atomic radii are 1.270A and 1.241 A respectively

Answer 1

In BCC there are 2 atoms per unit cell,

$a = \frac{4}{\sqrt3}r =\frac{4}{\sqrt3}\times1.270 =2.93$

an FCC crystal structure, 4 atoms per unit cell and

$a = 2 \sqrt2r =2\sqrt2\times1.241 =3.51$

percentage change as iron transforms from FCC to BCC $=\frac{3.51-2.93}{100}= 58$ %