The intrinsic mechanical damping or internal friction of a material is defined as the capacity of a material to convert the mechanical energy of vibrations and noises into heat, which is desirable in many construction materials, including Naval ship applications. Recently, Fe-Mn alloys are being developed and actively studied due to a balance of their high strength and damping capacity at large strain amplitudes at a relatively low cost. The high damping capacity of Fe-Mn alloys is known to be related to stacking faults and the epsilon-martensite phase transformation, resulting from a low stacking fault energy (SFE) in fcc austenitic alloys. The combination of high strength and damping capacity is suitable for military ship-building; however, at present the US steel community has only limited experience with these classes of steels. Herein, we are proposing to use an Integrated Computational Materials Engineering (ICME) approach to elucidate the fundamental microstructural and manufacturing processes in high-Mn steels with the following approach: (1) Thermodynamic and experimental evaluation of stacking fault energies and volume fractions of epsilon-martensite for strengthening and damping capacity of high-Mn steels; (2) Correlative atom-probe tomography (APT), transmission electron microscopy (TEM), and density-functional (DFT) calculation studies of the gamma/epsilon heterophase interface for damping capacity; (3) ICME of carbonitride precipitate strengthening and damping capacity in austenitic high-Mn steels; (4) Microstructural evolution and mechanical properties of the welded joints of high-Mn steels; (5) Damping capacity and mechanical properties of hydrogen-charged high Mn-steels; (6) Corrosion in saline solutions and oxidation studies of high-Mn steels. These research topics will provide technical and economical approaches for developing high damping Fe-Mn alloys for Naval ship applications.
|Effective start/end date||8/1/22 → 7/31/25|
- Office of Naval Research (N00014-22-1-2693)
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