Kinetics and Microstructural Control

· The displacive phase transition of austenite to martensite starts at grain boundaries and propagates through the grain at close to the speed of sound, the maximum velocity for the transmission of elastic information.
· Thin lenses of Martensite minimize lattice distortions at the coherent boundary with the lattice from which it formed.

From: Ashby & Jones, "Engineering Materials," Pergamon (1986)