A Literature Review of Age Hardening Fe-Mn-Al-C Alloys
This review of Fe-Mn-Al-C alloys reports on literature published between 1933 and 2008 on age hardenable Fe-Mn-Al-C alloys with chemistries in the range of 18-28 wt.% Mn, 9-12 wt.% Al, and 0.7-1.2 wt.% C. Fe-Mn-Al-C alloys possess low density (6.5-7.2 g/cm 3), tensile strengths from 600 to 2,000 MPa, elongation to failure as great as 70%, and they can exhibit high-energy absorption, e.g., 0.43 J/mm 3 at strain rates of 10 2 s-1. Solution treatment of FeMnAl alloys above 900°C produces either a fully austenitic or a duplex ferrite and austenite microstructure. Upon age hardening, a coherent (Fe,Mn) 3AlC carbide, known as κ-carbide, with a perovskite crystal structure precipitates In the austenite, and classic age hardening behavior is observed. Phase equilibria are reviewed as a function of alloy composition and temperature for solution-treated and age hardened alloys. Fatigue, fracture, and environmentally induced embrittlement phenomena are also reviewed. The combination of lower density, extensive formability, the ability to age harden, and to absorb energy in a crash makes the Fe-Mn-Al-C alloys a potential advanced high-strength steel candidate for the transportation industry. These steels may also be applied as a lightweight casting alloy for military armor. Lightweight steel alloys are sought to reduce the areal density of steel materials utilized for MIL-PRF-32269 perforated homogenous steel armor.
R. A. Howell and D. C. Van Aken, "A Literature Review of Age Hardening Fe-Mn-Al-C Alloys," Iron and Steel Technology, Association for Iron & Steel Technology (AIST), Jan 2009.
Materials Science and Engineering
Article - Journal
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