In an endeavor to achieve the critical goals of carbon neutrality, an explorative study was conducted to scrutinize the precipitate evolution and high-temperature creep behavior of an innovative and cost-effective Fe–Ni-based superalloy that was meticulously engineered for the next-generation ultra-supercritical (USC) power plants. The creep experiments conducted at temperatures and stresses of 650 °C/280 MPa (17,179 h), 675 °C/250 MPa (10,271 h), and 700 °C/250 MPa (2378 h), coupled with proficient data fitting were employed to accurately assess the long-term service performance of the superalloy under real-world operational environments. Though it can withstand theoretically an intense stress of 130 MPa at 700 °C for approximately 30 years as calculated by the Larson-Miller equation, its performance was not without a degree of perceived vulnerability. This was primarily traced to the conspicuous coarsening behavior of the precipitate-free zones (PFZs)/discontinuous coarsening zones (DCZs) formed in the grain boundaries (GBs) on a longer time scale. It had a significant diminishing impact on the overall strength of the GBs, resulting in a recorded creep life that was considerably shorter than initially projected. Moreover, a synergistic mechanism between PFZs/DCZs with TiC carbides was advanced to interpret the intergranular fracturing dynamic, which was postulated due to the evidence gathered from electron backscatter diffraction (EBSD), highlighting that the banded distribution of TiC carbides circumambient to GBs engendered considerable stress aggregation. Conversely, the plentiful supply of coincidence site lattice (CSL) boundaries disrupted the continuous network structure of random high-angle grain boundaries (HAGBs), thereby creating an effective barricade against the proliferation of cracks. These empirical findings paved the way for the proposition of an enhanced blueprint and the industrial utilization of such.

中文翻译：

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新设计的铁镍基高温合金中高温蠕变变形行为与纳米级析出物演变之间的相互作用

为了实现碳中和的关键目标，我们进行了一项探索性研究，以仔细研究一种创新且具有成本效益的铁镍基高温合金的析出物演变和高温蠕变行为，该合金是为下一代精心设计的超超临界（USC）发电厂。采用在 650 °C/280 MPa（17,179 h）、675 °C/250 MPa（10,271 h）和 700 °C/250 MPa（2378 h）的温度和应力下进行的蠕变实验，并结合熟练的数据拟合准确评估高温合金在实际操作环境下的长期使用性能。虽然根据拉森-米勒方程计算，理论上它可以承受 700°C 130 MPa 的强应力约 30 年，但其性能并非没有一定程度的脆弱性。这主要归因于较长时间尺度上晶界（GB）中形成的无沉淀物区（PFZ）/不连续粗化区（DCZ）的显着粗化行为。它对 GB 的整体强度产生了显着的减弱影响，导致记录的蠕变寿命比最初预计的要短得多。此外，还提出了 PFZ/DCZ 与 TiC 碳化物之间的协同机制来解释晶间断裂动力学，这是根据电子背散射衍射 (EBSD) 收集的证据而假设的，强调 TiC 碳化物围绕 GB 周围的带状分布产生了相当大的影响。应力聚集。相反，大量的重合点晶界（CSL）边界破坏了随机高角度晶界（HAGB）的连续网络结构，从而形成了阻止裂纹扩散的有效屏障。这些实证研究结果为增强蓝图的提出及其工业利用铺平了道路。