Mechanical properties of an ultrafine grained C–Mn steel processed by warm deformation and annealing

Fracture Behavior and Delamination Toughening of Molybdenum in Charpy Impact Tests

“…By a closer examination of the stressrelieved condition of the transversal sample (T), a slight increase of yield and tensile strength as well as a drop of fracture strain and uniform elongation can be observed. The same tendencies were found for stress-relieved molybdenum 4 and for an API-X80 pipeline steel, 27 which was explained by a closer spacing of grain boundaries in the transversal orientation.…”

“…[21][22][23] However, as structural materials are exposed to impact loadings, the Charpy impact test seems to be an adequate technique to gain a better understanding of fracture at high deformation speeds and low test temperatures at multi-axial stress states. 24,25,27 This testing method is, besides hardness and tensile tests, a common method for technical investigations in industry due to its simplicity. Charpy impact tests are a straightforward method to reveal brittleness caused by an increase of deformation speed or a decrease of test temperature, as it preferentially occurs in bcc metals.…”

“…In recent studies, the mechanical properties of pipeline steels and ultrafine-grained bcc steels have been, among other methods, characterized by Charpy impact tests. 27,28 In this work, Charpy impact tests are combined with advanced characterization techniques to relate mechanical properties to the microstructure of technically pure molybdenum. Tensile tests and Charpy impact tests were conducted on samples of a technically processed molybdenum plate to investigate the role of delamination and crystallography on the DBTT in order to give an overview of the DBTTs in differently oriented specimens of a technically pure molybdenum plate in its stress-relieved and recrystallized state.…”

“…This thin sheet toughening, which is also known as delamination toughening, occurs to a differing extent depending on the specimen orientation in respect to the grain shape. 4,[20][21][22][23][24][25][26][27] In previous studies, tensile tests were used to characterize the DBTT of molybdenum. Fracture toughness tests provided more accurate measurements of the DBTT for potential applications due to the predominant triaxial stress state during the experiments ahead of the crack tip.…”

Novel thermomechanical processing methods for achieving ultragrain refinement of low-carbon steel without heavy plastic deformation

“…It should be emphasized that a total strain of only 0.92 is required to obtain the sub-micron UFF structure in the two novel TMCP routes, which is much smaller than those previously reported in literatures. [28][29][30] Figure 5(c) indicates that the yield strengths obtained in the present study are within a broad band of Hall-Petch relationship for low-C steels, but locate at a higher level. It has been known that ultrafine-grained ferrite usually show limited uniform elongation due to early plastic instability.…”