Martensitic Transformations: Diffusionless Change
Explain how rapid coordinated atomic motion creates hard phases, shape change and transformation stresses.
A different transformation mechanism
Martensitic transformation occurs through coordinated lattice distortion rather than long-range diffusion. It can therefore proceed rapidly at low temperature.
Start and finish temperatures
Transformation progresses over a temperature interval. Composition, prior austenite structure and stress shift the start and finish conditions.
Shape and internal stress
The transformation strain creates plates, laths or needles and generates substantial internal stress. Variants form to accommodate shape change.
Beyond steel
Martensitic mechanisms also underpin shape-memory alloys, transformation-toughened ceramics and selected titanium alloys.
Engineering takeaway
Treat martensite as a transformation product with morphology, carbon content and tempering response—not as a single hardness value.