Tensile deformation of a low density Fe–27Mn–12Al–0.8C duplex steel in association with ordered phases at ambient temperature
Tensile deformation of a low density Fe–27Mn–12Al–0.8C duplex steel in association with ordered phases at ambient temperature
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DOI：
10.1016/j.msea.2013.07.094
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发表时间：
2013-12
期刊：
影响因子：
6.4
通讯作者：
M. C. Ha;J. Koo;Jae-Kon Lee;Si Woo Hwang;Kyung-Tae Park
中科院分区：
文献类型：
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作者：
M. C. Ha;J. Koo;Jae-Kon Lee;Si Woo Hwang;Kyung-Tae Park
研究了低密度Fe-27 Mn-12 Al-0.8C双相钢的室温拉伸行为与未变形组织和变形组织的关系，重点研究了有序相对塑性变形的影响。在（奥氏体+铁素体）两相区退火后，通过淬火形成各种有序相。在无序的铁素体基体中形成了由涡旋状热反相晶界包围的B2畴。除B2畴外，细小的D 03相均匀地分布在B2畴和无序的铁素体基体中。奥氏体中析出纳米级κ碳化物。该钢具有较高的屈服强度和较低的应变硬化速率，导致了适度的延伸率。钢的比强度达到~146 MPa cm 3/g。铁素体的变形结构表现为具有狭窄的机械反相边界的成对位错（超级位错）的短而直的段。在奥氏体中，在低应变下，单个平面位错滑移占主导地位，在高应变下发生多个平面滑移。基于这些微观结构的观察，它建议，钢的应变硬化主要是由剪切有序相的superdislocations（铁素体）和平面滑移位错（奥氏体）。此外，还将该双相钢的拉伸变形行为与其它低密度Fe 3 Mn 3Al 3C双相钢的拉伸变形行为进行了比较。
Room temperature tensile behavior of a low density Fe–27Mn–12Al–0.8C duplex steel was correlated with both undeformed and deformed microstructures, focusing on the effects of the ordered phases on plastic deformation. Various ordered phases were formed by quenching of the steel after annealing at the (austenite+ferrite) two phase region. The B2 domains bounded by swirled thermal antiphase boundaries were formed in disordered ferrite matrix. In addition to the B2 domains, fine D03phases were evenly distributed through both B2 domains and disordered ferrite matrix. The nano-sized κ carbides were precipitated in austenite. The steel exhibited the relatively high yield strength and the low strain hardening rate initially, leading to the moderate elongation. The specific strength of the steel reached ~146 MPa cm3/g. Deformed structure of ferrite is manifested by short, straight segments of paired dislocations (superdislocations) with narrow mechanical antiphase boundaries. In austenite, a single planar dislocation glide was dominant at low strains and multiple planar slip occurred at high strains. Based on these microstructural observations, it is suggested that strain hardening of the steel is dominated mainly by shearing of the ordered phases by superdislocations (in ferrite) and planar gliding dislocations (in austenite). In addition, the tensile deformation behavior of the present duplex steel was compared with that of other low density Fe3Mn3Al3C duplex steels.