Effect of the internal oxidation on the mechanical properties

众所周知，内部氧化对材料的有害影响，以及在ODS合金中产生微结构的可能性。在这两种情况下，氧气从表面扩散到材料中，以氧化合金中不太贵重的成分。目前讨论的扩散路径是通过金属基体的扩散和沿金属/氧化物非相干相边界的扩散。氧通过氧化物相的扩散通常被认为可以忽略不计，因为氧化物中的扩散通常比金属基体中的扩散要低得多。但是，如果形成导氧氧化物，通过氧化相的扩散也可以成为内部氧化的速率控制步骤。一个例子就是Ni-Zr-Y体系。YSZ是在内部氧化过程中形成的，以其导氧特性而闻名。与经典理论相比，该体系的氧化速率可提高三个数量级。形成了自组织、互穿的氧化物和金属网络。这个项目的目的是描述基于氧通过氧化相扩散的内部氧化的潜力和局限性。这包括进一步的合金系统的识别，以及在这些微观结构的材料性能的研究。

Internal oxidation is known for its detrimental effects on materials as well as for the possibility to produce microstructures like in ODS alloys. In both cases oxygen diffuses from the surface into the material in order to oxidize the less noble components of the alloy. The diffusion paths that are discussed at the moment are the diffusion through the metallic matrix and the diffusion along the incoherent phase boundaries metal/oxide. Oxygen diffusion through the oxide phase is often regarded as negligible as the diffusion in oxides is often much lower than in the metallic matrix. But the diffusion through the oxide phase can also be the rate controlling step for the internal oxidation if oxygen conducting oxides are formed. An example therefore is the system Ni-Zr-Y. There YSZ is formed during internal oxidation which is well known for its oxygen conducting properties. Oxidation rates in this system can be increased by three orders of magnitude compared to classical theory. Self-organized, interpenetrating networks of oxide and metal are formed. The aim of this project is to describe the potential and limitations of the internal oxidation that is based on the oxygen diffusion through the oxide phase. This includes the identification of further alloy systems as well as the investigation of material properties in those microstructures.