The Effect of Test Temperature on Deformation Microstructure and Fracture Mechanisms in CrMn High-Nitrogen Steels Alloyed (0-3 wt.%) with Vanadium
A temperature dependence of the tensile mechanical properties, microstructure and fracture mechanism of high-nitrogen Fe-(19-23)Cr-(17-21)Mn-(0-3)V-(0.1-0.3)C-(0.5-0.9)N vanadium-free and vanadium-containing steels was investigated. For all steels, the 0.2% offset yield strength and strain-hardening drastically increase with a decrease in test temperature. This is associated with high interstitial solid solution strengthening of the steels and more pronounced twinning and stacking-fault formation during straining below room temperature. For the vanadium-free steel, a ductile-to-brittle transition was evaluated: at 77K specimens destroy by cleavage mechanism while at room temperature steels show ductile fracture. Vanadium-alloying provides a particle strengthening of the steels and, at the same time, reduce solid-solution strengthening. Increase of vanadium concentration fully or partially suppress brittle fracture of the steels at 77K. Particle strengthening changes interstitial solid-solution effect, dislocation arrangement and slip/twinning relation in vanadium-containing high-nitrogen steels compared to vanadium-free one.
R. Shabadi, Mihail Ionescu, M. Jeandin, C. Richard and Tara Chandra
E. Astafurova et al., "The Effect of Test Temperature on Deformation Microstructure and Fracture Mechanisms in CrMn High-Nitrogen Steels Alloyed (0-3 wt.%) with Vanadium", Materials Science Forum, Vol. 941, pp. 27-32, 2018