Anomalous Strain Rate Dependence of the Serrated Flow in Ni-H and Ni-C-H Alloys.

摘要

Serrated flow in Ni-H, Ni-C-H, and Ni-C alloys was studied over a wide range of temperature and strain rates. The results for C related serrated flow in Ni-C or Ni-C-H alloys were in excellent agreement with previous results and were consistent with dislocation pinning by C solutes at the dislocation cores. Hydrogen related serrated yielding was observed in Ni-H and Ni-H-C alloys. Solute C had only a small effect on the temperature range of this H related serrated flow. The results could be interpreted on the basis of hydride formation at the dislocation cores and diffusion of H in these hydrides. Keywords: Nickel; Nickel alloys; Hydrogen; Serrated flow; Portevin-LeChatalier effect; Dislocations; Stress Strain relations.