Combined AEM/APFIM characterization of Alloy X-750

摘要

In the development of advanced alloys for power system applications, the primary emphasis is placed on attaining specific mechanical properties with resistance to environmental attack. An important part of alloy development is the detailed characterization of the microstructure, because it is the composition, size and morphology of the microstructural features that define the mechanical properties of the material. The good mechanical properties of Ni-base superalloys are a result of the formation of fine coherent precipitates. Analytical electron microscopy (AEM) provides important information concerning the type and distribution of the phases in the alloys, but quantitative microchemical analysis for the ultra-fine precipitates is not readily obtainable with conventional AEM techniques. The high optical resolution of the atom probe field-ion microscope (APFIM) make this technique ideally suited to the analysis of the ultra-fine precipitates and surrounding matrix. In this paper, a combined AEM/APFIM study of precipitation in Alloy X-750 is presented.