Influence of precipitate and grain sizes on the brittle-to-ductile transition in Fe-Al-V bcc-L21 ferritic superalloys
Influence of precipitate and grain sizes on the brittle-to-ductile transition in Fe-Al-V bcc-L21 ferritic superalloys
复制标题
析出相和晶粒尺寸对 Fe-Al-V bcc-L21 铁素体高温合金脆塑转变的影响
DOI：
10.1016/j.msea.2022.144031
复制
发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Ferreirós P
中科院分区：
文献类型：
--
作者：
Ferreirós P
实现体心立方高温合金的广泛应用的限制因素是高的脆韧转变温度（BDTT）。了解的机制控制BDTT和如何优化的微观结构在多晶体心立方高温合金仍然是一个问题today.In目前的工作中，晶粒和共格沉淀物的尺寸对强度和脆韧性转变温度（BDTT）的影响进行了研究在Fe 78 Al 10 V 12（A2+L21）铁素体高温合金，走向应用在高效率的发电厂。此外，A2矩阵行为进行了评估，在派生的单相bcc的Fe 84 Al 8V8合金。热老化和粗化处理，以产生不同的沉淀物和晶粒尺寸的样品。在不同的温度和应变速率下进行拉伸试验，以评估屈服应力的变化。夏比冲击试验用于测量两种合金中的BDTT，其随着晶粒尺寸细化和沉淀物粗化而显著降低。有人发现，在解理应力的增加沉淀强化遵循相同的行为，在屈服应力的增加，共格强化体心立方高温合金。集成到一个基于物理的模型，它确定了一个新的相互作用与解理应力，提供了增强的BDTT预测能力的铁素体高温合金。
The limiting factors to achieving a wide application of bcc-superalloys are the high brittle-to-ductile transition temperatures (BDTT). The understanding of the mechanisms controlling the BDTT and how to optimise the microstructure in polycrystalline bcc-superalloys remains a concern today.In the present work, the influence of grain and coherent precipitates sizes on strength and brittle-to-ductile transition temperature (BDTT) are studied in a Fe78Al10V12(A2+L21) ferritic superalloy, toward application in high-efficiency power plants. Additionally, the A2 matrix behaviour was evaluated in a derived single-phase-bcc Fe84Al8V8alloy. Thermal ageing and coarsening treatments were applied to produce samples with different precipitate and grain sizes. Tensile tests were carried out at different temperatures and strain rates to assess the variation of the yield stress. Charpy impact tests were used to measure the BDTT in both alloys, which was substantially reduced with grain size refinement, and precipitate coarsening. It was found that the increase in cleavage stress by precipitation strengthening follows the same behaviour that the increase in yield stress for coherent strengthened bcc-superalloys. Integration into a physical-based model, which identified a novel interplay with cleavage stress, provides enhanced BDTT predictive capability for ferritic superalloys.