What does expansion type work means in thermodynamics

dear sandeep 
expansion means the volume of the gas will increase in the system , 
as far as expansion work is concerned ,. 
in the case of free expansion , work is done agnaist external pressure , which is 0 , hence , work done = p ( ext ) * del v =0 
in case of free expansion , no heat is gained or loss by the body . 
hence , by the frst law , change in internal energy is 0 . 
HOPE IT CLEARS 
REGARDS