Martensitic Transformation
A rapid, diffusionless solid-state phase transformation driven by collective lattice shear displacement of atoms.
Governing formula
Diffusionless shear transformation: Austenite (FCC) → Martensite (BCT)
SI unit
Transformation Temperature M_s
In depth
Quenching hot austenite steel rapidly prevents carbon diffusion, trapping carbon in a distorted Body-Centered Tetragonal (BCT) martensite lattice that exhibits extreme hardness and high internal stress.
Examples in the real world
Water-quenching red-hot high-carbon steel to produce extremely hard martensitic tool steel.