3. In FCC iron, carbon atoms are located at octahedral sites at the center of each edge of the unit cell(1/2, 0,0) and at the center of the unit cell (1/2, 1/2, 1/2).In BCC iron. carbon atoms enter tetrahedral sites, such as (1/4, 12, 0). The lattice parameter is 0. 3571 nm for FCC iron and 0.2866 nm for BCc iron. Assume that carbon atoms have a radius of 0.071 nm o Would we expect a greater distortion of the crystal by an interstitial carbon atom in FCC or BCc iron? 2 What would be the atomic percentage of carbon in each type of iron if all the interstitial sites were filled? Solution: O For BCC iron √3) (√3(0.2866) CC 0.124lnm 43. In FCC iron, carbon atoms are located at octahedral sites at the center of each edge of the unit cell (1/2,0,0) and at the center of the unit cell (1/2, 1/2, 1/2). In BCC iron, carbon atoms enter tetrahedral sites, such as (1/4,1/2,0). The lattice parameter is 0.3571 nm for FCC iron and 0.2866 nm for BCC iron. Assume that carbon atoms have a radius of 0.071 nm.  Would we expect a greater distortion of the crystal by an interstitial carbon atom in FCC or BCC iron?  What would be the atomic percentage of carbon in each type of iron if all the interstitial sites were filled?  For BCC iron: 0.1241nm 4 ( 3)(0.2866) 4 3 0 BCC    a R