Studies on Microstructure Evolution and Mechanical Properties in Structural Metallic Materials by in-situ Neutron Diffraction

Abstract

Mechanical properties, as the principal properties of structural metallic materials, are governed by the microstructures. To track the structure-property relationship associated with various solid-solid reactions such as phase transformation and plastic deformation, is crucial for the development of structural metallic materials. These dynamic solid-solid reactions occur in various extreme environments, including thermomechanical controlled process, cryogenic deformation, fatigue, etc., and are nearly impossible to be directly observed by conventional techniques. Neutron diffraction can provide crystallographic information such as phase fraction, lattice strain (stress), texture, dislocation density. This information can provide unique insights into microstructure evolution and deformation mechanisms in bulky materials. TAKUMI, an engineering materials diffractometer at MLF, J-PARC, covering a large d-range with a good balance between high neutron flux and high resolution, possessing advanced sample environments, is reliable for tracking the structure-property relationship associated with various solid-solid reactions under extreme environments. In the present paper, several recent studies associated with microstructure evolution and deformation mechanisms in steels and magnesium alloys investigated by in-situ neutron diffraction with TAKUMI are introduced.