报告题目(中文)：利用同步辐射研究激光辅助3-D打印镍基超级合金中的缺陷和应力不均匀性

报告题目(英文)：A synchrotron study of defect and strain inhomogeneity in laser-assisted 3D-printed Ni-based superalloy

报告内容简介：Synchrotron X-ray microdiffraction was employed to investigate the inhomogeneous distribution of defect and residual strain in the transitional region between the dendritic and stray grains in a laser-assisted 3D printed Ni-based superalloy. The dendritic region was found to be under tensile strain transversely to the primary dendrite arm directions. The dendrite edges, where high level of strains and geometrically necessary dislocations were detected, were discerned as low angle grain boundaries. High angle grain boundaries were observed in the stray grain region, and the orientation of the strain tensor in this region varied dramatically at the micron scale, in contrast with the more or less homogeneous distribution in the dendritic region.

报告人姓名：陈凯

报告人简介(中文)：西安交通大学副教授，国家青年千人（2011），教育部新世纪人才（2012），博士（2009，UCLA材料科学与工程系），博士后（2009-2011，加州大学伯克利分校和伯克利国家实验室），学士（2005，北京大学化学系）

研究领域： Study of microstructures such as orientation, strain/stress, twinning, and texture in crystals including metals, alloys, ceramics, and minerals using microscopy (SEM, TEM, orientation imaging microscopy) and diffraction techniques (X-ray diffraction, neutron diffraction, and electron diffraction) In situ investigation of structural and property evolution in crystalline materials at micro/nano scale using synchrotron X-ray microdiffraction and electron microscopy techniques Reliability analysis of structural and functional materials Development of diffraction data analysis softwares

代表性论文： 1.Kai Chen, N. Tamura, M. Kunz, K. N. Tu, and Yi-Shao Lai In situ measurement of electromigration-induced transient stress in Pb-free Sn-Cu solder joints by synchrotron radiation based X-ray polychromatic microdiffraction Journal of Applied Physics, 106, 023502, 2009 2.Kai Chen, N. Tamura, Wei Tang, M. Kunz, Yi-Chia Chou, K. N. Tu, and Yi-Shao Lai High precision thermal stress study on flip chips by synchrotron polychromatic X-ray microdiffraction Journal of Applied Physics, 107, 063502, 2010 3.Catherine Dejoie, Martin Kunz, Nobumichi Tamura, Colin Bousige, Kai Chen, Simon Teat, Christine Beavers, and Christian Baerlocher Determining the energy-dependent X-ray flux variation of a synchrotron beamline using Laue diffraction patterns Journal of Applied Crystallography, 44, 177-183, 2011 4.Hua Guo*, Kai Chen*, J. Oh, S. A. Syed Asif, O. L. Warren, Z. Shan, Kevin Wang, J. Wu, and A. M. Minor (* joint first author) Mechanics and Dynamics of the Strain-Induced M1-M2 Structural Phase Transition in Individual VO2 Nanowires Nano Letters, 11, 3207-3213, 2011 5.Kai Chen, Catherine Dejoie, and H.R. Wenk Unambiguous indexing of trigonal crystals from white beam Laue diffraction patterns: Application to Dauphiné twinning and lattice stress mapping in deformed quartz Journal of Applied Crystallography, 45, 982-989, 2012 6.Kai Chen, Martin Kunz, Nobumichi Tamura, and Hans-Rudolf Wenk Residual stress preserved in quartz from the San Andreas Fault Observatory at Depth Geology, 43(3), 219-222, 2015 7.Yao Li, Liang Wan, and Kai Chen* A look-up table based approach to characterize crystal twinning for synchrotron X-ray Laue microdiffraction scans Journal of Applied Crystallography, 48(3), DOI:10.1107/S1600576715004896, 2015

报告人单位：西安交通大学

报告时间：2015-09-25 09:30

报告地点：材料楼520会议室

主办单位：上海大学材料学院