THE MICROSTRUCTURE OF THE 1.4914 MANET MARTENSITIC STEEL BEFORE AND AFTER IRRADIATION WITH 590 MEV PROTONS

Optical and transmission electron microscope observations, together with SEM (scanning electron microscope) and ASTEM (analytical scanning transmission electron microscope) microanalysis have been performed in samples of the DIN 1.4914 martensitic steel (MANET cast), both before and after irradiation with 590 MeV protons to doses up to 1 dpa at temperatures between 363 and 703 K. The chemical composition of the different carbide geometries have been obtained. No substantial modification of the carbide and precipitate structure is observed after either deformation under fatigue or after irradiation to 1 dpa at 703 K. No bubbles have been observed in a specimen irradiated to 0.7 dpa, containing 87 appm He.