Microstructural change in austenitic Fe-30.0wt%Mn-7.8wt%Al-1.3wt%C initiated by spinodal decomposition and its influence on mechanical properties

Journal Article · Mon Dec 01 04:00:00 EST 1997 · Acta Materialia

DOI:https://doi.org/10.1016/S1359-6454(97)00201-2· OSTI ID:599682

Choo, W K; Kim, J H ^[1]; Yoon, J C ^[2]

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1. Korea Advanced Inst. of Science and Technology, Taejon (Korea, Republic of). Dept. of Materials Science and Engineering
2. Research Inst. of Industrial Science and Technology, Pohang (Korea, Republic of)

The microstructural change of supersaturated austenitic Fe-30.0 wt% Mn-7.8 wt% Al-1.3 wt% C allow on aging at 823 K has been investigated by transmission electron microscopy (TEM) and X-ray diffraction. Efforts to correlate the modulation wavelength behavior with mechanical properties in the process of spinodal decomposition leading to the cubic {kappa}{prime}-carbide (Fe,Mn){sub 3}AlC{sub x} formation have been made. In parallel with the modulation wavelength coarsening behavior, both the microhardness and the tensile strength increase in two stages during aging. The first stage strengthening coincides with the slow growth spinodal decomposition, while the second occurs at the Lifshiftz-Slyozov-Wagner (LSW) growth stage of ordered {kappa}{prime} particles. By the optimal aging treatment of the alloy, a high yield strength up to 1,080 MPa with an excellent 31.5% elongation can be attained. After further aging, the alloy softened rapidly, and its elongation deteriorated drastically due to the formation of the grain boundary lamellar colonies composed of discontinuously coarsened {kappa} carbide and transformed {alpha} ferrite phases.

• OSTI ID: 599682
• Journal Information: Acta Materialia, Journal Name: Acta Materialia Journal Issue: 12 Vol. 45; ISSN 1359-6454; ISSN ACMAFD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AGE HARDENING
AUSTENITIC STEELS
MANGANESE STEELS
MECHANICAL PROPERTIES
MICROSTRUCTURE