Microstructure and Properties of a Low-Density Steel with High Strength of 1350 MPa
A low-density steel Fe-20Mn-10Al-1.0C with high strength of 1350 MPa was developed. The mechanical properties and microstructure evolutions of Fe-20Mn-10Al-1.0C steel under various heat treatment conditions were investigated by means of optical microscopy, X-ray diffraction and high resolution elect...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | zho |
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Journal of Aeronautical Materials
2018-10-01
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| Series: | Journal of Aeronautical Materials |
| Subjects: | |
| Online Access: | http://jam.biam.ac.cn/CN/Y2018/V38/I5/67 |
| Summary: | A low-density steel Fe-20Mn-10Al-1.0C with high strength of 1350 MPa was developed. The mechanical properties and microstructure evolutions of Fe-20Mn-10Al-1.0C steel under various heat treatment conditions were investigated by means of optical microscopy, X-ray diffraction and high resolution electron microscopy. The results show that the alloy goes through spinodal decomposition leading to the L′1<sub>2</sub> ordered phase-κ′ carbide (Fe, Mn)<sub>3</sub>AlC<i><sub>x</sub></i> formation. After solution-treatment at 950 ℃, diffused precipitates of (Fe, Mn)<sub>3</sub>AlC<i><sub>x</sub></i> with the sizes of 2-5 nm are formed inside the austenite substrate. After the subsequent ageing process, the size of κ′ carbides is increased, and the particles tend to be aligned and agglomerated along the <100> directions with the aging temperature increases. Periodic modulated structures are finally formed into resembling regular "checkered lattice". Ordering effect strengthening by the nano-sized κ′ carbides and elastic misfit strengthening by spinodal decomposition cause a high tensile strength up to 1350 MPa with a good elongation, and the density is lower than 6.80 g/cm<sup>3</sup>. |
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| ISSN: | 1005-5053 1005-5053 |