报告题目：In Situ Measurement of Radiation Damage with Transient Grating Spectroscopy

报告人：Michael Short（美国麻省理工学院）

报告时间：2018年6月7日14:00-15:30（周四）

报告地点：大学城校区B5栋-102会议室

欢迎广大师生参加！

报告人简介：

Michael Short joined the faculty in the Department of Nuclear Science and Engineering in July, 2013. He brings 15 years of research experience in the field of nuclear materials, microstructural characterization, and alloy development. His group’s research is a mixture of large-scale experiments, micro/nanoscale characterization, and multiphysics modeling & simulation. The main areas of Short’s research focus on 1) Non-contact, non-destructive measurement of irradiated material properties using transient grating spectroscopy (TGS) more, 2) Preventing the deposition of deleterious phases, such as CRUD in nuclear reactors, as fouling deposits in energy systems more, and 3) Quantification of radiation damage by stored energy fingerprints more. This last project was recently selected for an NSF CAREER award.

报告摘要：

Materials issues are the main factors holding back life extension of light water reactors and deployment of advanced reactors. Radiation damage still limits the lifetime of current and future nuclear reactors, but our ability to quickly gauge its extent is severely limited. In this talk, we will introduce our improvement [4] and application of transient grating spectroscopy (TGS) [1-5] to study how materials behave during irradiation on the mesoscale. Changes in thermal diffusivity are linked to defect clustering and radiation induced segregation (RIS) in both pure metals and neutron-irradiated steels, while changes in stiffness correlate strongly to the onset of void swelling. This technique reduces the time to acquire key knowledge of material property changes under irradiation from months to hours, greatly speeding up our ability to better understand radiation resistant materials, and gauge their lifetimes in nuclear applications.

A number of studies will be presented along this theme, demonstrating the utility of this new technique for radiation materials science. We will specifically show how changes in surface acoustic wave (SAW) speed, which directly link to Young’s Modulus and Poisson’s ratio, can identify the radiation dose in DPA to the onset of void swelling in single crystal copper and nickel. Radiation-dependent changes in thermal diffusivity help show the saturation of radiation-induced dislocations and defect clustering in single-crystal niobium irradiated with Si ions, while the same thermal diffusivity changes reveal the onset and saturation of radiation induced segregation in neutron-irradiated 304 stainless steel to 28 DPA. Finally, a number of studies, ranging from deducing thermal properties of irradiated carbon nanotube coatings, MAX phase materials, tungsten fuzz development for fusion applications, and illustrating temperature-dependent radiation effects in SiC will be shown to show the broad applicability of TGS.