Effect of volume fraction of bainite on strain hardening behavior and deformation mechanism of F/B multi-phase steel
Effect of volume fraction of bainite on strain hardening behavior and deformation mechanism of F/B multi-phase steel
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DOI：
10.1016/j.msea.2018.06.016
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发表时间：
2018-07-25
期刊：
影响因子：
6.4
通讯作者：
Chen, Y. B.
中科院分区：
文献类型：
--
作者：
Tang, C. J.;Shang, C. J.;Chen, Y. B.
采用热机械控制工艺（TMCP）对5种不同贝氏体体积分数的铁素体/贝氏体（F/B）复相试验钢进行了加工。采用修正C-J分析、Hollomon分析和数值模拟方法研究了F/B复相钢的应变硬化行为和变形机制。研究表明，第一阶段的变形机制与铁素体的弹塑性变形直接相关，第二阶段的变形机制与铁素体和贝氏体的均匀应变（变形）直接相关。随着贝氏体体积分数的增加，铁素体和贝氏体的变形机制由非协调变形转变为协调变形，导致铁素体和贝氏体之间的应变差逐渐减小，这可能是修正C-J分析中三阶段转变为两阶段的原因。实验验证了其变形机理。此外，通过修正C-J分析中各阶段的划分和应变硬化能力，解释了贝氏体体积分数对屈服应力/拉应力比（屈强比）、应变硬化指数和均匀延伸率的影响。
Five ferrite/bainite (F/B) multi-phase experimental steels with different volume fraction of bainite were processed by thermo-mechanical controlled processing (TMCP). The strain hardening behavior and deformation mechanism of F/B multi-phase steel were studied by modified C-J analysis, Hollomon analysis and numerical simulation method. The study indicates that the deformation mechanism in stage I and stage II are directly related to elastic-plastic deformation of ferrite and uniform strain (deformation) of ferrite and bainite, respectively. As the volume fraction of bainite increases, the deformation mechanism of ferrite and bainite changes from incoordinate deformation to coordinate deformation, which will cause the strain difference between ferrite and bainite being lessened gradually, as well as might be the reason for the transition from three-stage to two-stage in modified C-J analysis. The deformation mechanism was verified experimentally. Moreover, the effect of volume fraction of bainite on yield stress/tensile stress ratio (yield ratio), strain hardening exponent and uniform elongation were explained by the division and strain hardening capability of the stages in modified C-J analysis.