Phase Transition of High Carbon Steel Demonstration

The Materials Science and Technology Teacher's Workshop (MAST) provides this demonstration on the phase transition of high carbon steel. The crystalline structure of iron is different at different temperatures, and high-carbon steel alloys undergo a transformation from BCC to FCC in a very small temperature range. An interesting application of this theory is in determining the maximum temperature to which a piece of steel has been heated before it changes phases. In this module, a piece of piano wire is heated and phase changes are observed through the changes in length and magnetic properties of the wire. The lesson includes a step by step explanation of the laboratory procedure. Discussion questions are also included.