The Strain-Rate and Temperature Dependence of 18Ni(350) Maraging Steel Tensile Properties

Abstract

The influence of microstructure, strain rate, and test temperature on the tensile properties of 18Ni(350) maraging steel was examined. The strain-rate and temperature dependence of the yield strength is less than that observed in low-strength carbon steels. The results suggest that the thermally activated flow process involves both the by-passing of a linear barrier, i.e., the disruption associated with a dislocation core, and the by-passing of a localized obstacle, the latter being specific to the microstructure being examined. The tensile ductility of aged 18Ni(350) maraging steel also undergoes a ductile-brittle transition. The extent of this ductility loss depends upon the matrix solute content and the presence of either reverted austenite or a highly dislocated substructure.