Microstructural evolution and mechanical properties of fusion welds in an iron-copper-based multicomponent steel

Jeffrey D. Farren*, Allen H. Hunter, John N. Dupont, David N. Seidman, Charles V. Robino, Ernst Kozeschnik

*Corresponding author for this work

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

NUCu-140 is a copper-precipitation-strengthened steel that exhibits excellent mechanical properties with a relatively simple chemical composition and processing schedule. As a result, NUCu-140 is a candidate material for use in many naval and structural applications. Before NUCu-140 can be implemented as a replacement for currently used materials, the weldability of this material must be determined under a wide range of welding conditions. This research represents an initial step toward understanding the microstructural and mechanical property evolution that occurs during fusion welding of NUCu-140. Microhardness traverses and tensi letesting using digital image correlation show local softening in the heat-affected zone (HAZ). Microstructural characterization using light optical microscopy (LOM) revealed very few differences in the softened regions compared with the base metal. Local-electrode atom-probe (LEAP) tomography demonstrates that local softening occurs as a result of dissolution of the Cu-rich precipitates. MatCalc kinetic simulations (Vienna, Austria) were combined with welding heat-flow calculations to model the precipitate evolution within the HAZ. Reasonably good agreement was obtained between the measured and calculated precipitate radii, number density, and volume fraction of the Cu-rich precipitates in the weld. These results were used with a precipitate-strengthening model to understand strength variations within the HAZ.

Original languageEnglish (US)
Pages (from-to)4155-4170
Number of pages16
JournalMetallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
Volume43
Issue number11
DOIs
StatePublished - Nov 1 2012

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys

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