Martensitic transformation

Martensite most commonly refers to the quench constituent in steel; it’s named after the well-known German metallurgist Adolf Martens. If steel is quenched from high temperature phase called austenite, its hardness will increase.

Martensitic transformation is a phase transformation at solid state which can be summarized in 3 key points:

  • Transformation without diffusion (no atoms travel). There is no chemical composition modification in the material.
  • Deformation of the crystal lattice which leads to a change of the macroscopic shape (fig. 1) characterized by a low volume variation (in the SMA) and significant shearing along a well-defined plan.
  • Different variants of equivalent orientations are created (fig.2), in order to minimize the interaction energy between martensite created and asutenite still existing.