This answer is very necessary for me..please reply soon..some options for this answer are magnalium,manganese steel,type metal,duralium...answer is among these four options
Edit: So I just went through my Chem text book. And it should be Magnalium.
Because it's composed of Magnesium and Aluminum and both of those elements expand on solidifying even though it's not by much.
Oops xD haha.
Dude, you expect us to do your homework? It's called reading a book!