Characteristics 上游充道大粤 SHANGHAI JIAO TONG UNIVERSITY 2.Diffusionless Austenite Martensite:only crystal structure change but no composition change Atoms change position in a regimented manner (coordinated movement)>neighboring atoms keep the same after transformation Experimental support:martensite transformation can occur at temperature as low as 4K,when the atomic diffusion rate is so small that transformation can not take place through atomic diffusion at all! K.Chen 9K. Chen Characteristics 9 2. Diffusionless Austenite  Martensite: only crystal structure change but no composition change Atoms change position in a regimented manner (coordinated movement)  neighboring atoms keep the same after transformation Experimental support: martensite transformation can occur at temperature as low as 4K, when the atomic diffusion rate is so small that transformation can not take place through atomic diffusion at all!