The influence of texture and impurities on the mechanical behavior of zirconium

Development of physically-based constitutive models capable of simultaneously describing slip, twinning, and anisotropy requires knowledge of the coincident influence of each on mechanical response. The effects of interstitial impurities and texture on twinning in zirconium (Zr), in addition to variations in strain rate and temperature are utilized to probe substructure evolution and mechanical behavior. The compressive yield response of high-purity crystal-bar and commercial-purity Zr was found to depend on the loading orientation relative to the h.c.p. c-axis, the applied strain rate, varied between 0.001 and 3500/s, and the test temperature, varied between 76 and 298K. The rate of strain hardening in Zr is seen to depend on the controlling defect storage mechanism as a function of texture, strain rate, and temperature. The substructure evolution of high-purity Zr was observed to depend on the applied strain rate and test temperature; the substructure of high-purity Zr was seen to display a greater incidence of deformation twinning when deformed at high strain rate or quasi-statically at 76K. copyright 1998 American Institute of Physics