In this paper

the TEM research results on the rnicrcotructure of adia- batic shear band(ASB)in various metallic material have been reviewed.These have mainly dealt with microstructural characteristic of ASB

the discussion of the nature of“white- etching band”in steel

the evolution mechanism and the contro- versy corresponding to the mechanism. The reviewed results have shown that the central structure of ASB consist mainly of very fine equiaxial grains(less then 0.5um in diameter)and that the nature of“white- etching band”in steel is not the particular indication of untempering martensite. Meanwhile

it has been proved to be extremely inaccurate that

previously

ASB had been classified into “deformed band”or“transfomed band”on the basis of ASB's appearance.