But cooled very quickly, they at the outset crystallize as a homogeneous phase, but they are supersaturated with the secondary constituents. Otherwise, some alloys can also have their properties altered by heat treatment. This causes the iron crystals to deform as the crystal structure tries to change en route for its low temperature state, departure those crystals very hard although much less ductile more breakable. In ancient Egypt and Mycenaegold was often alloyed with copper to produce red-gold, or flatten to produce a bright burgundy-gold. This is sometimes a answer of the sizes of the atoms in the alloy, as larger atoms exert a compressive force on neighboring atoms, after that smaller atoms exert a tensile force on their neighbors, helping the alloy resist deformation.