What are alloys? Name an important alloy which contains some of the lanthanoid metals. Mention its uses.

(N/A) An alloy is a solid solution of two or more elements in a metallic matrix. It can either be a partial solid solution or a complete solid solution. Alloys usually possess different physical properties than those of the component elements.
An important alloy of lanthanoids is Mischmetal. It contains lanthanoids $(94-95 \%)$,iron $(5 \%)$,and traces of $S$,$C$,$Si$,$Ca$,and $Al$.
Uses:
$(1)$ Mischmetal is used in cigarette and gas lighters.
$(2)$ It is used in flame-throwing tanks.
$(3)$ It is used in tracer bullets and shells.