Internal stresses and carbon enrichment in austenite of Quenching and Partitioning steels from high energy X-ray diffraction experiments
Internal stresses and carbon enrichment in austenite of Quenching and Partitioning steels from high energy X-ray diffraction experiments
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DOI：
10.1016/j.msea.2017.10.105
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发表时间：
2018-01-05
期刊：
影响因子：
6.4
通讯作者：
Poulon-Quintin, Angeline
中科院分区：
文献类型：
--
作者：
Allain, Sebastien Yves Pierre;Gaudez, Steve;Poulon-Quintin, Angeline
淬火和分配（Q & P）工艺允许生产含有大部分富碳残留奥氏体的创新显微组织。本研究强调，奥氏体在这种热循环过程中产生显着的内应力。机械和化学贡献都可能影响其在室温下的稳定性，从而影响钢的机械性能。通过高能X射线衍射（HEXRD）进行的实验明确地表明奥氏体中的内应力源自马氏体相变应变以及在再加热至配分温度和最终冷却期间引起的附加静水应力。这些本征应变归因于马氏体和奥氏体之间的热膨胀系数（CTE）的差异，并成功地预测了一个纯粹的弹性平均场的方法。在本研究中，残余奥氏体被证明是在压缩在室温下。因此，这种应力状态有助于稳定残余奥氏体以抵抗在室温下可能的应变诱导的转变，并且影响测定奥氏体中的碳含量的方式。
Quenching and Partitioning (Q & P) process permits to produce innovative microstructures containing large fraction of carbon enriched retained austenite. The present study highlights that austenite undergoes significant internal stresses generated during such thermal cycle. Both mechanical and chemical contributions are likely to affect its stability at room temperature and thus the resulting mechanical properties of the steel. The experiments carried out by High Energy X-Ray Diffraction (HEXRD) show unambiguously that internal stresses in austenite originate from martensitic transformation strain and from additional hydrostatic stresses induced during both reheating to partitioning temperature and final cooling. These eigenstrains are attributed to the difference in Coefficients of Thermal Expansion (CTE) between martensite and austenite and are predicted successfully with a purely elastic mean field approach. In the present study, retained austenite is shown to be in compression at room temperature. As a consequence, this state of stress contributes to stabilize retained austenite against a possible strain induced transformation at room temperature and affects the way to determine the carbon content in austenite.