Monday  |  Salon 13  |  04:50 PM–05:10 PM

#15758, On the Transition from Shear Banding to Fracture in Metals: Insights from in-situ Observations

Using direct high-speed imaging, we study a mode of failure in high strain-rate deformation of metals where localized plastic flow inside shear bands acts as a precursor to fracture. In this study, a two-dimensional cutting configuration is used to impose large strain deformation under controlled rates of shear. A range of outcomes in the material behavior -- homogeneous flow, highly localized shear banding, partial fracture along the shear band, to complete material separation -- is demonstrated using the same geometry by simply varying the shearing rate. Shear band formation, localized flow development, and subsequent dynamics of material separation and fracture are quantitatively characterized using in-situ imaging and full-field image correlation techniques. It is shown that a critical stress criterion governs the first transition from homogeneous flow to shear banding, while the evidence suggests localized flow to fracture transition may follow a strain-based rule. Implications of shear banding and fracture for machining and deformation-based processes will be discussed.

Shwetabh Yadav   Indian Institute of Technology Hyderabad
Harshit Chawla   Texas A&M University
Dinakar Sagapuram   Texas A&M University