FORMATION AND DEVELOPMENT OF SHEAR DEFORMATION LOCALIZATION IN LOW CARBON STEELS
钢中剪切变形局部化的形成与发展

The formation,development and microstructure of shear localization formed during dynamic high speed tornsional testing by split Hopkinson bar with a average strain rate range of 600,650 and 1500 s-1 have been investigated in low-carbon steels.The results showed that the shear localization is sensitive to the strength of the steel.The higher the strength of the steel,the earlier the shear localization occurs.The observations by TEM indicated that the formation and development of the shear localization involved a series of the crystallographic and non-crystallographic events including the dislocation emission from the interfaces between the precipitate and matrix,forming network,cell and tangled structures of the dislocations;the misorientation formation arising from the large accumulated plastic strain in a local area in the band and the growth and coalescence of the microcracks in the band leading to a sharp drop in the load-carrying capacity of the deformed material.