A study of twinning in zirconium using neutron diffraction and polycrystalline modeling

Abstract

An experimental study using neutron diffraction quantified the evolution of twinning in pure clockrolled zirconium that was subsequently deformed under uniaxial compression. The clock rolling introduced an initial texture of approximately 5 times random, and the compression specimens were cut with their loading axes nearly parallel to the predominant c-axes direction. Seven specimens deformed to strains between −2 and −17 pct and an undeformed specimen (0 pct strain) were examined. The deformation was performed at an applied strain rate of 0.001/s at 77 K. Twin volume fractions were estimated from diffraction data. Changes in texture and twin volume fractions were compared to predictions from a visco-plastic self-consistent (VPSC) polycrystal model, which described both slip and twinning. This work demonstrates the feasibility of using neutron diffraction to track the evolution of twinning. These results help benchmark the polycrystalline model, validate the description of twinning, and potentially lead to a better understanding of its role in hardening.