Fundamental Principals of Phase Transformations, Strength and Toughness in High-Strength 10 wt.% Ni Steels for US Naval Applications

Project: Research project

Project Details

Description

We are proposing to employ a scientific physical metallurgy based approach in combination with Integrated Computational Materials Engineering (ICME) to elucidate the fundamental processes of phase transformations, microstructural evolution, and strengthening and toughening mechanisms in 10 wt.% Ni high-strength high-toughness steels, with respect to processing routes and thermal history, with the goal to develop a detailed understanding of the favorable combination of mechanical properties in the base steel, as well as in fusion welded, weld-simulated, mechanically deformed, and samples exposed to corrosive environments. Specifically, austenite reversion, carbide precipitation, formation and tempering of martensite, will be studied with a focus on how these processes affect mechanical properties, tensile strength, plasticity, fracture toughness, as a function of processing routes. Micro-segregation, homo- and heterophase-interfaces including martensite lath boundaries and prior austenite grain boundaries, and localized interfacial segregation, will be our focus because they are key factors governing the mechanical properties. We will study the microstructure in multi-pass weldments with a focus on the fusion zone and melt-pool, effects of solidification and thermal cycling on micro-segregation and microstructure in the weld filler and base metal. We will correlate the microstructural and atomistic results obtained from experiments, calculations and simulations (ICME) with the mechanical properties (yield strength, ultimate tensile strength, plasticity, toughness, and highstrain-rate deformation). We will study susceptibility and mechanisms of hydrogen-induced embrittlement and cracking, stress-corrosion cracking, and related corrosion phenomena in typical marine (saline) environments.
StatusActive
Effective start/end date4/13/214/12/24

Funding

  • Office of Naval Research (N00014-21-1-2398)

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