In: Chemistry
A cubic metal (radius of hypothetical touching atomic spheres:
r=0.77Å) shows
plastic deformation by slip along the<111>directions. Based
on this
information, deduce the planar packing density (atoms/m2) for its
densest family
of planes.
Since there is a slip along <111> directtions, it should be a BCC system with a slip {110}, <111>
Therefore, in this case : a x cube root ( 3 ) = 4r
or, a = 4r / cube root (3 )
Substituting the given value of r = 0.77Ao = 0.77 x 10-10 m we get,
a = 4 x 0.77 x 10-10 / cube root (3) = 2.14 x 10-10 m
Now densest planes are {110 } so packing density is -
2 atoms / { a2 SQRT (2) } = 2 / [ 2.14 x 10-10 ]2 x 1.4142 = 3 .0883 x 1019 atoms / m2
or, = 3 x 1019 atoms / m2