Development of adiabatic shear bands in annealed 316L stainless steel: Part II. TEM studies of the evolution of microstructure during deformation localization

摘要

The evolution of adiabatic shear localization in an annealed AISI 316L stainless steel has been investigated and was reported in Part I of this paper (Met. Trans. A, 2006, Vol. 37A, pp. 2435–446). In the present research (Part II), a comprehensive transmission electron microscopy (TEM) examination was conducted on the microstructural evolution of shear localization in this material at different loading stages. The TEM results indicate that elongated subgrain laths and an avalanche of dislocation cells are the major characteristics in an initiated band. Development of the substructures within shear bands is controlled by dynamic recovery and continuous dynamic recrystallization. The core of shear bands was found to consist of fine equiaxed subgrains. Well-developed shear bands are filled with a mixture of equiaxed, rectangular, and elongated subgrains. The equiaxed subgrains, with a typical size less than 100 nm, are postulated to result from either the breakdown and splitting of subgrain laths or the reconstruction of subcells.