DIFFERENT MATERIAL IN SINGLE WELDAMENT

dear friends,
i have created one weldaments made up of diffrent plates and library parts.
i want to give plates are one material and library parts are different material.
but i couldnt make.
i can define only one material.
what is the solution to give different material in single weldament.

kindly reply me

jeyaprakashSolidworksWeldments