School of Materials Science and Engineering Dalian University of Technology

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2017-06-05 08:14     (点击: )



主讲人:郭恩宇 英国曼彻斯特大学




Solidification is an extremely complicated process where the liquid is transformed to the solid state through a complex interfacial interactions introduced by a wide range of affecting parameters, such as the alloying elements, thermal conditions, etc. Understanding thetime-evolved (4D, 3D+time)microstructures is essential to establish the underlying solidification mechanisms and finally to control the microstructures to improve the material quality.In situsynchrotron X-ray tomography offers a unique tool to quantify microstructural evolution in multiphase materials, allowing the kinetics of transformations to be quantified in real time. In this talk, I will start with introduction into the principles of implementing X-ray tomography. Twosolidification-related4Dcase studiesconducted in theDiamond Light Source (DLS, UK)will be covered: (1) Dendritic formationand coarseningduring solidification of Mg alloys; (2) Microstructurestabilityin a multi-phase soft material, ice cream, under applied thermal cycling. A bespoke high temperature furnace and a cold stage were incorporated into the synchrotron beamline I13 of DLS to provide the sample environment in studies of case1and2, respectively. Inbothcases, critical features will be rendered in 3D, analyzed and discussed. The results in this talk can be taken as important cases to validate and develop solidification mechanisms and explicitly prove the importance of using X-ray tomography in thisthe solidificationsubject.


郭恩宇博士现为英国曼彻斯特大学材料学院研究助理(2014.09-至今),其博士毕业于清华大学(2014.01),期间在美国亚利桑那州立大学进行公派留学博士联合培养(2012.09-2013.08)并随后在该校进行博士后研究工作(2014.03-2014.08)。郭恩宇博士的研究工作主要集中在:(1)材料凝固过程的3D/4D组织演化;例如,目前,正采用同步辐射高能X-射线原位(in situ)实验针对镁合金中的枝晶多样性选择以及组织粗化展开深入研究;(2)材料在跨尺度(宏/介/微观)条件下的力学行为表征及其评估;研究手段主要包括扫描电镜中的原位拉伸力学实验,FIB微柱压缩技术以及纳米压痕技术等;(3)材料三维结构表征及定量化;采用大型同步辐射X-射线(英国钻石光源DLS,上海光源SSRF等主要同步辐射大科学装置)、实验室X-射线以及聚焦离子束FIB和金相序列层磨等综合三维结构表征技术研究多相材料3D结构。至今,已在Acta Mater., J. All. Compd, Mater. Sci. Eng. A等发表论文25篇,受邀做国际学术会议与国内邀请报告7次。近年来,作为项目骨干参与多项国内与国际项目,包括国家自然科学基金(1项)、国家重大科技高档数控机床04专项子项及专项平台建设项目(2项)、欧盟框架FP-7项目(1项)、美国海军办公室项目(1项),国内外工业资助项目(3项)等;起草教育部博士点基金并获立项1项,申请英国大型设备基金(英国钻石光源)4项,并开发工程应用软件一套(软件著作权)。