Caucasian_Asian140s aren't metal. Sorry, but they aren't.
Old Salomon 916s are have a lot of metal. FKS/Pivot 15/18s have a lot of metal. Tyrolia MOJO/Peak 15/17/18/20s do too.
No bindings are purely metal. they all have plastic parts that wear out. Toe wings on every binding will break. Same with AFDs. Even the FKS18 has some composite in the heels that will wear out or break.