What material are pins of a microcontroller typically made of?
Wikipedia suggests it may be FeNi42:


  The lead frame (and therefore the pins, if any, formed from that lead
  frame) are occasionally made from FeNi42, a kind of Invar.


I remember reading somewhere that the leads of most components — resistors, capacitors, IC pins and the like — are made of steel. Turns out to be the cheapest material suitable for the task.