Peculiarities of plastic flow involving “deformation waves” observed during low-temperature tensile tests of highly irradiated 12Cr18Ni10Ti and 08Cr16Ni11Mo3 steels

Abstract

In a previous paper, it was shown that the expectation that neutron irradiation of low-nickel austenitic steels leads to a low saturation level of ductility is not always valid. At high dose ductility is observed first to decrease with dpa during room temperature testing and then under some conditions to increase at higher dose. This produces anomalously high deformation arising from a previously unrecognized mechanism that precludes sustained necking and produces a moving deformation front. It was earlier speculated that this behavior is a result of α-martensite formation in the deforming region. New studies involving testing over −115 to +120 °C confirm that the γ → α transformation is involved with this deformation mechanism and is the cause of the recaptured ductility. When the irradiated alloy has not yet reached the dose threshold of wave initiation at room temperature a decrease in test temperature can induce wave generation, consistent with the known effect of temperature on martensite instability.