Rate Dependence of Stainless Steel 21Cr-6Ni-9Mn

Many metals exhibit increasing yield strength as the loading rate is increased by orders of magnitude. This phenomenon has been documented for many materials, but literature values can vary considerably. Also, the rate dependence of other structural properties is sparsely documented. In this work, stress-strain curves of 21Cr-6Ni-9Mn stainless steel were obtained at strain rates from 10^-4 to 10² s^-1. Strain was measured using high speed digital image correlation. The rate-dependence of yield strength was quantified by direct measurements at these rates. Values were compared to data obtained using the strain rate jump method and to published literature. In addition to characterizing the rate dependence of yield stress, this work characterized the rate dependence of other structural properties—most notably ductility, but also including ultimate tensile strength, uniform elongation, and apparent elastic modulus. Finally, similar measurements were made on cold worked material to assess how cold working affects strain rate dependence of structural properties. SNL is managed and operated by NTESS under DOE NNSA contract DE-NA000352