Dislocation substructure developed in martensitic steels under thermal fatigue

I ALVAREZ; A ARMAS; C PETERSEN

JOURNAL OF NUCLEAR MATERIALS

Elsevier

Año: 1992 vol. 191- p. 841 - 844

0022-3115

. Thermal fatigue tests were carried out on a martensitic steel, DIN denomination W. Nr. 1.4914, commonly named MANET I. The tests were performed in air by allowing the sample to serve as its own heater and converting any longitudinal thermal deformation of the specimen into elastic or inelastic deformation. The low temperature was held constant and equal to 473 K and variable values, 823, 873, 923, 973 K for the high temperature were selected. The effects of different thermal cycling ranges on the mechanical behavior and the accompanying microstructural changes in the specimen were evaluated. A continous softening preceded by a stability period was observed in all thermal fatigue tests. Higher temperature changes produce an accelerated softening process. The original lath structure evolves to a mixed structure of expanded laths and subgrains or a fully subgrain structure depending on the temperature range