Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7971583 | Materials Science and Engineering: A | 2018 | 21 Pages |
Abstract
The recrystallization behavior of a high-Mn high-Al lightweight steel (Fe-28.4Mn-8.3Al-1.27â¯C (wt%)) with 50% cold rolling deformation is investigated at the annealing temperature of 800â¯Â°C, 900â¯Â°C and 1000â¯Â°C. The detailed microstructure evolution is characterized by optical microscopy (OM), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), X-ray diffraction (XRD), electron probe micro-analyzer (EPMA) and transmission electron microscopy (TEM). The partial recrystallized bimodal austenite grains and κ-phase (Fe, Mn)3AlC form at 800â¯Â°C, while fully recrystallized austenite grains without κ-phase appear at 900â¯Â°C and 1000â¯Â°C. With the increase in annealing temperature, the increased frequency of annealing twin boundaries reduces the average austenitic grain size and the dispersion of the austenite grain size effectively. The effect of austenite grain size on the tensile properties is discussed. The strain hardening behavior is also investigated by Hollomon analysis and C-J analysis, and the later one is better to explain the strain hardening behavior in different four stages. The recrystallization behavior significantly improves the tensile toughness from 59 MJ/m3 to 436 MJ/m3 at the expense of tensile strength decrease from 1460â¯MPa to 890â¯MPa, due to the homogenous fine austenite grains and high frequency of high misorientation angle. The steel with fully recrystallized austenite grains of 10.0â¯Âµm annealed at 900â¯Â°C exhibits the optimum mechanical properties with excellent tensile strength of 965â¯MPa, ductility of 48.3%, and good toughness of 400 MJ/m3.
Keywords
Related Topics
Physical Sciences and Engineering
Materials Science
Materials Science (General)
Authors
Fengqin Ji, Wenwen Song, Yan Ma, Chengning Li, Wolfgang Bleck, Guodong Wang,