Bend yield stresses in tungsten sheet

Abstract

Recrystallized tungsten sheet tested in bending at temperatures just above the ductile-brittle transition temperature displays marked discontinuities on the load-deflection curve. These discontinuities bear a striking resemblance to yield point inflections. Their temperature dependencies are the same as those reported for tensile yield stresses in tungsten. They also show a strong dependence on grain size on a Hall-Petch type plot. However, better relationships are obtained by using an exponent other than − 1 2 or by breaking the d − 1 2 curve into segments corresponding to different parts of the grain size-annealing temperature curve. This suggests that the annealing treatment contributes to the grain size dependence of the bend yield stresses.