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High Temperature Superalloys and Hierarchical Microstructures

国家重点实验室学术讲座

SKL-AMM Seminar

题目/Title:High Temperature Superalloys and Hierarchical Microstructures

报告人/Speaker:Dr. Florian Vogel

Affiliation:Technical University of Berlin

Institute of Materials Science and Technology,

Department Structure and Properties of Materials

日期/Date:20181121(星期三), Nov. 21 (Wednesday), 2018

时间/Time:10:30 - 11:30 AM

联系人/Contact郑为为 副教授(zhengww@skl.ustb.edu.cn)

报告地点/Location:北京科技大学主楼 353, 353 Main Building, USTB

报告摘要/Abstract

    Understanding phase separation phenomena enables tailoring microstructures of high temperature alloys to achieve improved mechanical properties. High resolution characterization techniques are used to understand the link between structure-property relationships and the 3D nanochemistry of hierarchical microstructures in high temperature superalloys. In the presented research, transmission electron microscopy and atom probe tomography were utilized to understand the phase separation of ordered precipitates in a Ni-based superalloy having a hierarchical microstructure. The chemical and microstructural evolution of disordered particles inside L12 and D03 ordered precipitates, respectively is elucidated. In the Ni-based alloy, disordered (A1) spherical γ particles form inside ordered (L12) precipitates and undergo a morphological change to plates which further grow and eventually split the γ′ precipitates. The presence of these γ particles increases the mechanical properties.  It was found that ordered precipitates are supersaturated in Ni, respectively, thus driving the formation of disordered particles. The microstructural evolution is accompanied by a compositional evolution resulting in an energetically more favorable state. The results suggest that by controlling the supersaturation the phase separation can be harnessed to tune the properties of such materials.

作者简介/Speaker’s short biography

 Dr. Vogel is currently a scientist at TU Berlin where he employs high resolution characterization techniques such as transmission electron microscopy and atom probe tomography to research both the fundamental processes that form microstructures and their 3D nanochemistry at atomic scale to develop new avenues for tailoring advantageous properties in superalloys with hierarchical microstructures. He received his Ph.D. in Materials Science and Engineering from the Technical University of Berlin, Germany, in 2014. After earning his Ph.D. he continued to work as a post-doctoral research fellow at TU Berlin and Helmholtz Center Berlin for Materials and Energy where became head of Atom Probe Tomography Laboratory. In 2016 he joined the research Group of Prof. G.B. Thompson at the University of Alabama Tuscaloosa, USA, performing research on nanocrystaline low-dimensional materials, shape memory alloys, aluminum alloys, ultra high temperature ceramics and superalloys with a special focus on applying advanced atom probe tomography techniques to understand structure-property relationships and develop next generation engineering materials. Dr. Vogel is currently the principal investigator of two projects, one funded by the German Research Foundation (DFG) and one funded by the National Natural Science Foundation of China (NSFC). He may be reached at: vogel@tu-berlin.de.