Nanocluster formation in oxide-dispersion strengthened steels by internal oxidation subsequent to ultrasonic powder atomization

超声粉末雾化后通过内部氧化在氧化物弥散强化钢中形成纳米团簇

• 批准号: 462420328
• 负责人: Professor Dr.-Ing. Martin Heilmaier
• 金额: --
• 依托单位: Institut für Angewandte Materialien - Werkstoffkunde (IAM-WK)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/462420328?language=en
• 关键词: Nanocluster; formation; oxide; dispersion; strengthened

The proposed project deals with the fundamental issue in processing oxide dispersion strengthened steels of how oxide nanoclusters form from the severely deformed microstructure subsequent to mechanical alloying. In this project, we utilize ultrasonic metal powder atomization for this purpose, which allows the preparation of metal powders lean in interstitials. During ultrasonic metal powder atomization, the raw material is melted in an arc melter the crucible of which is attached to an ultrasonic sonotrode. The vibrations of the sonotrode lead to tear off of molten particles and rapid solidification to spherical particles with narrow size distribution occurs. The use of arc melting and low gas flow allows for achieving very low interstitial contents. These are below or in the order of the oxygen contents needed to form oxide nanoclusters whereas in mechanical alloyed steels a tremendous oxygen excess exists which makes the analysis of the solved oxygen content and precipitation state of the oxides difficult. After atomization, the nanoclusters are formed via internal oxidation. During the project, the chemical composition, the microstructure and the mechanical properties are determined throughout the entire processing chain. This includes an evaluation of oxide particle size and density, dislocation density and grain size by scale-bridging characterization techniques. This allows for an assessment of the precipitation sequences during the processing steps and its influence on the mechanical behavior of the materials.

拟议的项目涉及加工氧化物弥散强化钢的基本问题，即机械合金化后如何从严重变形的微观结构中形成氧化物纳米团簇。在这个项目中，我们利用超声波金属粉末雾化来实现此目的，这使得可以制备出贫间隙的金属粉末。在超声波金属粉末雾化过程中，原材料在电弧熔化器中熔化，该熔化器的坩埚连接到超声波焊极。超声波发生器的振动导致熔融颗粒撕裂并快速凝固成具有窄尺寸分布的球形颗粒。使用电弧熔化和低气流可以实现非常低的间隙含量。这些低于或约为形成氧化物纳米团簇所需的氧含量，而在机械合金钢中存在巨大的氧过量，这使得分析溶解的氧含量和氧化物的沉淀状态变得困难。雾化后，通过内氧化形成纳米团簇。在项目期间，化学成分、微观结构和机械性能在整个加工链中得到确定。这包括通过尺度桥接表征技术评估氧化物颗粒尺寸和密度、位错密度和晶粒尺寸。这样可以评估加工步骤期间的沉淀序列及其对材料机械行为的影响。