In situ study of granular micromechanics in semi-solid carbon steels

The granular micromechanics of semi-solid steel at ∼80% solid are studied by synchrotron radiography. A particulate soil mechanics approach to image analysis shows that deformation occurs by the translation and rotation of quasi-rigid grains under the action of contact forces, and that the changes in directional fabric and grain–grain contacts occur by mechanisms similar to those of highly compacted soils including “locked sands”. Grain-scale phenomena are then linked to the macroscopic displacement and strain fields and it is shown that shear-induced dilation is a fundamental response at both the grain and macro scales. Based on this, recommendations are made on future rheology experiments.