
Structure of
metals
31
Figure 2.4 Growth of
a
metal dendrite (From Higgins, R.
A.,
Properties
of Engineering
Materials,
Hodder and Stoughton)
change a solid, at its melting point, to a liquid without any change in
temperature occurring; this energy is called latent heat. Similarly, when a
liquid at the fusion point (i.e. the melting point) changes to a solid, energy has
to be removed, no change in temperature occurring during the change of state;
this is the latent heat. Thus, when the liquid metal in the immediate vicinity of
the metal crystal face solidifies, energy is released which warms up the liquid in
front ofthat advancing crystal face ...