Investigation of Transformation Pathways in A High Entropy Alloy with A Complex Nanoscale Microstructure Using Advanced Electron Microscopy
讲座名称：
Investigation of Transformation Pathways in A High Entropy Alloy with A Complex Nanoscale Microstructure Using Advanced Electron Microscopy
讲座时间：
2017-10-17
讲座人：
Hamish L. Fraser
形式：
校区：
兴庆校区
实践学分：
讲座内容：
讲座名称：Investigation of Transformation Pathways in A High Entropy Alloy with A Complex Nanoscale Microstructure Using Advanced Electron Microscopy
讲座时间：2017年10月17日，上午10：00
讲座地点：西二楼A102，曲江校区
讲座人：Prof. Hamish L. Fraser
Center for the Accelerated Maturation of Materials,
The Ohio State University
讲座内容：High-entropy alloys (HEAs) are a new class of materials garnering a great deal of attention due to their intriguing balance of properties, including high strength, ductility, and corrosion resistance. They appear to offer new pathways to lightweighting in structural applications, but to realize this potential requires considerable alloy development that will rely on integrated computational materials engineering (ICME) and a detailed knowledge of the microstructural evolution of these compositionally complex alloys. One such HEA, AlMo0.5NbTa0.5TiZr, was selected to be the basis for this characterization study due to its strength at elevated temperature, low density, and interesting nanoscale interpenetrating microstructure. HEA samples were vacuum arc-melted followed by hot isostatic pressing and homogenization at 1400 ºC for 24 hours with a furnace cool of 10 ºC/min in an inert gas atmosphere. Samples were quenched at various times during the furnace cool and have been characterized using optical, scanning electron microscopy, and aberration-corrected transmission electron microscopy. Additionally, scanning transmission electron microscopy (STEM) based tomography has been used to provide detailed 3D reconstructions of the microstructure. From this materials characterization and the heat-treatment study, the transformation pathway has been determined to involve a disorder – order transition followed by spinodal decomposition. This has been simulated using computational thermodynamics and phase field modeling.
相关视频