Properties of alloys

(1) Thermal and electrical conductivities :

These properties of a solid solution are less than those of the pure metals.

• According to mathieessens's rule when small quantities of an alloying element are added in solid solution to a metal the increase in resistance does not depend upon the temperature.

For the mixture of insoluble phase, thermal and electrical resistance follow the law of mixture.

(2) Density:

Density is increased by heavier metal in solid solution and is decreased by a lighter metal.

In case of interstitial solid solution, there is little effect on density by the added element.

(3) Specific heat and co-efficient of thermal expansion:

These properties of alloys are governed by the law of mixture.

(4) Melting point:

The greater the difference in valencies between the metal of alloys the wider is the melting range.

(5) Boiling point:

The boiling point (like melting point) is also converted into a range by the addition of alloying element.