Guo Jinming, Haberfehlner Georg, Rosalie Julian, Li Lei, Duarte María Jazmin, Kothleitner Gerald, Dehm Gerhard, He Yunbin, Pippan Reinhard, Zhang Zaoli
Erich Schmid Institute of Materials Science, Austrian Academy of Sciences, Leoben, 8700, Austria.
Institute for Electron Microscopy and Nanoanalysis, Graz University of Technology, Steyrergasse 17, Graz, 8010, Austria.
Nat Commun. 2018 Mar 5;9(1):946. doi: 10.1038/s41467-018-03288-8.
Oxygen contamination is a problem which inevitably occurs during severe plastic deformation of metallic powders by exposure to air. Although this contamination can change the morphology and properties of the consolidated materials, there is a lack of detailed information about the behavior of oxygen in nanocrystalline alloys. In this study, aberration-corrected high-resolution transmission electron microscopy and associated techniques are used to investigate the behavior of oxygen during in situ heating of highly strained Cu-Fe alloys. Contrary to expectations, oxide formation occurs prior to the decomposition of the metastable Cu-Fe solid solution. This oxide formation commences at relatively low temperatures, generating nanosized clusters of firstly CuO and later FeO. The orientation relationship between these clusters and the matrix differs from that observed in conventional steels. These findings provide a direct observation of oxide formation in single-phase Cu-Fe composites and offer a pathway for the design of nanocrystalline materials strengthened by oxide dispersions.
氧污染是金属粉末在暴露于空气中进行严重塑性变形过程中不可避免会出现的问题。尽管这种污染会改变固结材料的形态和性能，但关于纳米晶合金中氧行为的详细信息却很缺乏。在本研究中，使用像差校正高分辨率透射电子显微镜及相关技术来研究高应变Cu-Fe合金原位加热过程中氧的行为。与预期相反，在亚稳Cu-Fe固溶体分解之前就发生了氧化物的形成。这种氧化物的形成在相对较低的温度下开始，首先生成纳米尺寸的CuO团簇，随后是FeO团簇。这些团簇与基体之间的取向关系不同于传统钢中观察到的情况。这些发现提供了对单相Cu-Fe复合材料中氧化物形成的直接观察，并为通过氧化物弥散强化的纳米晶材料设计提供了一条途径。
