Short-term stress relaxation on cyclic lattice-strains evolution of a new martensitic steel at elevated temperature via in-situ ND

A new 9Cr martensitic steel MARBN for next generation power plant is shown to have a superior mechanical performance comparing with existing other 9Cr steels in high temperature applications. The additional short-term dwell period of power plant operations is extremely detrimental to experience creep-fatigue, which has already been regarded as the key failure mechanism of the high temperature components. The proposed experiment aims to gain an in-depth physical understanding on the micro-mechanics strains evolution induced by the short-term stress relaxation on lattice-strains development through Neutron Diffraction, providing more insights of such material in high temperature applications. The proposed in-situ ND measurements will be interpreted using a crystal plasticity finite element model to accounting for direct interaction between a single crystal and its neighbouring crystals.