Influence of aging and thermomechanical treatments on the mechanical properties of a nanocluster-strengthened ferritic steel

Z. W. Zhang, C. T. Liu, Y. R. Wen, A. Hirata, S. Guo, G. Chen, M. W. Chen, Bryan A. Chin

    Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

    46 Citations (Scopus)

    Abstract

    This study investigated the effect of aging and thermomechanical treatments on the mechanical properties of a nanocluster-strengthened ferritic steel, Fe-1.5Mn-2.5Cu-4.0Ni-1.0Al (wt pct). The effect of thermomechanical treatments on the microhardness and tensile properties were measured at room temperature and correlated with microstructural features. Cu-rich precipitates were characterized by transmission electron microscopy and were found to coarsen slowly during long-time aging. The microhardness measurements indicate a typical precipitation hardening behavior during aging at 773 K (500 °C). Tensile tests showed that thermomechanical treatments can improve the mechanical strength and ductility of the nanocluster-strengthened ferritic steel significantly compared with those without the treatments. Fractography results indicated that the high yield strength resulted from precipitation hardening makes the steel more susceptible to grain-boundary decohesion, which can be suppressed by grain refinement. Atmosphere adsorption and diffusion along grain boundaries were found to intensify brittle intergranular fracture, and this embrittlement can be avoided by vacuum heat treatment. © 2011 The Minerals, Metals & Materials Society and ASM International.
    Original languageEnglish
    Pages (from-to)351-359
    JournalMetallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
    Volume43
    Issue number1
    DOIs
    Publication statusPublished - Jan 2012

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