To control steel quality during continuous casting and subsequent heat treatment, an understanding of the evolution laws of mechanical properties during the austenite transition and the underlying mechanisms is of importance. Herein, the peak separation method is used to investigate the expansion behaviors in low‐carbon steel. And the elastic properties of the matrix phase are calculated using the exact muffin‐tin orbitals (EMTO) method. A continuous evolution model of high‐temperature properties in the phase‐transition region is established for ab initio data and experimental results. The evolution laws of the tetragonal shear elastic constant C′ and Young's modulus E agree well with that of the high‐temperature strength. The critical temperature for ductility to brittleness is 850 °C. The matrix phase exhibits significantly brittleness character and increases slightly with decreasing temperature in single‐phase paramagnetic (PM) γ‐Fe region. The straightening zone temperature should be controlled above 950 °C to avoid cracks. In the austenite transition region, the drop rate of the magnetic moment reaches 18.90%. The findings suggest that the evolution law of mechanical properties of steels can be predicted from the elastic properties, especially during the austenite transition process, providing a basis for the prediction of material properties using ab initio methods.

中文翻译：

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低碳钢相变区力学性能连续演化的从头算研究

为了控制连续铸造和随后的热处理过程中的钢质量，了解奥氏体转变过程中机械性能的演变规律及其潜在机理非常重要。本文中，峰分离法用于研究低碳钢中的膨胀行为。然后使用精确的松饼锡轨道（EMTO）方法计算基体相的弹性。为从头算数据和实验结果建立了相变区高温特性的连续演化模型。四方剪切弹性常数C '和杨氏模量E的演化规律与高温强度非常吻合。延性至脆性的临界温度为850°C。在单相顺磁（PM）γ-Fe区，基体相表现出明显的脆性，并随温度的降低而略有增加。矫直区温度应控制在950°C以上，以免出现裂纹。在奥氏体转变区域，磁矩的下降率达到18.90％。这些发现表明，可以从弹性性能，尤其是在奥氏体转变过程中，预测钢的力学性能的演变规律，这为使用从头算方法预测材料性能提供了基础。