# Structure property-solid state transformations (finding the effective driving force)

1. Aug 9, 2011

### haamed

1. sorry if i posted this in the wrong section;
A new solid phase (β) nucleates homogeneously from a supersaturated solid
solution (α). The embryo is of spherical shape.
What do you understand to be the effective driving force? Calculate the
effective driving force for the transformation using the following data:

interfacial energy γαβ = 15 x 10-3 J m 2
r* = 0.4 x 10-9 m

2. the free energy change for the formation of spherical particle is given by

∆G HOM = 4/3 πr^3 ∆Gv + 4πr^2 γαβ + 4/3 πr^3 W

∴ ∆G HOM = 4/3 πr^3 (∆Gv+W) 4πr^2 γαβ

3. (∆Gv+W) is the effective driving force, using the radius and γαβ i have worked out so far;

4.7 x 10-28 (∆Gv+W) + 3.01 x 10-20

at this point i get stuck, do i need to rearrange the formula to make ∆Gv+W the subject and expand out of the brackets? it boggles the mind.
any help would be greatly appreciated