Investigations on microstructural aspects of adiabaticshear localization under strain rate 10$^{3}$s$^{ - 1}$ to 10$^{4}$ s$^{ -1}$ using EBSD-SEM, TEM and HREM are critically reviewed. The principalfeatures are: the critical condition for the occurrence of shear-bandsshould involve both shear strain and strain rate; the deformed-band formsfirst and the white-etching band follows with further shear deformation;the presence of white-etching bands is generally indicated by differentetching response of the narrow bands; shear band seems to initiate with acrystallographic slip in a favored grain and then propagates into theadjacent grains by co-operative slip or cross-slip, leading to the shearlocalization over the whole cross-section; both grain refinement andtransition from crystalline to amorphous can occur in shear bands; the$\gamma\to\varepsilon\to\alpha'$ transformation may also occur and the new transformed products have acertain orientation relationship with their parent matrix; the sharp drop inthe load-carrying capability of the specimen seems to be closely associatedwith the appearance of a critical coalescence of microcracks or voids in theband; the equiaxed-and distorted-free grains are proposed to attribute tothe rotational recrystallization. On the other hand, the micro-mechanism ofshear localization and fracture subjected to quasi-static and fatigueloadings is different from the dynamic case, namely caused by thedislocation planner slip and not related to thermal effects.Additionally, some further research are suggested.
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