Sanicro 25 austenitic heat-resistant steel is expected to be used in superheaters and reheaters for ultra-supercritical power plants above 600 °C due to its excellent structural stability and high temperature mechanical properties. In this paper, the effects of Co and W on the structural stability, thermodynamic stability and mechanical properties of Sanicro 25 steel are analyzed by calculating the formation energy, binding energy, Gibbs free energy, elastic constant, Peierls stress and generalized stacking fault energy (GSFE) with first-principles calculation method. By calculating the formation energy, binding energy and Gibbs free energy, it concludes that alloying elements Co and W in Sanicro 25 steel can improve the structural stability and thermodynamic stability. It indicates that W and a small amount of Co can improve the plasticity and ductility of Sanicro 25 steel by calculating the bulk modulus (B), shear modulus (G), Young’s modulus (E), the B/G ratio, Poisson’s ratio and Peierls stress. It is found that when Co and W are far from the stacking fault region, it will promote the formation of partial dislocations and twins in the system, thereby improving its plastic deformation ability and mechanical properties.

中文翻译：

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钴和钨对奥氏体耐热钢Sanicro 25的结构稳定性和力学性能的影响：第一性原理研究

Sanicro 25奥氏体耐热钢由于其出色的结构稳定性和高温机械性能，有望用于600°C以上的超超临界电厂的过热器和再热器中。本文通过计算形成能，结合能，吉布斯自由能，弹性常数，Peierls应力和广义堆垛层错能，分析了Co和W对Sanicro 25钢的结构稳定性，热力学稳定性和力学性能的影响（ GSFE）的第一原理计算方法。通过计算形成能，结合能和吉布斯自由能，可以得出结论，Sanicro 25钢中的Co和W合金元素可以改善结构稳定性和热力学稳定性。B），剪切模量（G），杨氏模量（E），B / G比，泊松比和Peierls应力。研究发现，当Co和W远离堆垛层错区域时，会促进体系中部分位错和孪晶的形成，从而提高其塑性变形能力和力学性能。