During homogeneous solidification of a liquid metal, the radius of critical nucleus (in nanometer, nm) at a temperature Ts which is below the melting point (Tm), is nm (round-off to one decimal place). Given that Ysl (solid liquid interfacial energy) is 0.18 J.m2 and AG, (change in volume free energy upon transformation from liquid to solid) at Ts is 0.18 10 J.m.