The effect of ion beam radiation on the mechanical properties of metallic alloys – studies on the micron scale (08/01/24)
Speaker and Affliation:
Dr. Dhriti Bhattacharya
Principal Radiation Damage Scientist
Australia’s Nuclear Science and Technology Organisation (ANSTO)
When?
8th January, 2024 (Monday), 4.15 PM (India Standard Time)
Where
K I Vasu Auditorium, Dept. of Materials Engineering, IISc, Bangalore
Abstract:
Ion beam irradiation experiments are performed to simulate the effect of neutron radiation on metallic materials in order to drastically reduce the time for observable radiation damage - which can vary from months to years in a nuclear reactor - to a few hours. Although ion beam irradiation cannot completely duplicate the irradiation conditions in neutron irradiation, it allows for the study of fundamental processes due to radiation damage at high doses, which are not achievable in practical time scales in neutron irradiation. This method also obviates the problem of radioactivity that is encountered in neutron irradiated samples. Ion irradiation experiments can cause damage similar to that found in the nuclear reactors, such as voids, bubbles, dislocation loops, vacancy and interstitial clusters, and other defects. Such damage causes an increase in strength and is usually accompanied by a decrease in ductility, which is extremely deleterious to the service properties of these materials in a reactor environment. However, one of the main issues faced in characterizing the effects of such damage arising out of ion irradiation is that it is confined to a small layer near the surface of the sample, typically ranging from a few hundred nm to a few microns. In this talk, the speaker will endeavour to show the various approaches used to evaluate the mechanical property changes in materials affected by ion irradiation, utilizing different techniques such as electron microscopy, nanoindentation and in situ micromechanical testing. Some interesting results and case studies will also be considered, which will help illuminate the phenomena occurring during the irradiation process, and show the utility of the micromechanical testing methods adopted here for evaluating ion irradiated materials.
Biosketch:
Dr. Dhriti Bhattacharyya is currently working as the Principal Radiation Damage Scientist at ANSTO. He did his Bachelor of Technology (B.Tech.) in Metallurgical Engineering from Indian Institute of Technology, Varanasi, India in 1995, and after a few years as Engineer in BHEL, India, went on to do his Ph.D. in Materials Science and Engineering from The Ohio State University, and graduated in 2004. He then worked as a Post Doctoral researcher at OSU and at Los Alamos National Laboratory, till 2010. His research activities there focused on the microstructure and mechanical properties of nanoscale multilayers and Zr alloys, and the effects of radiation damage on these materials. He has been working as a senior scientist at ANSTO, NSW, Australia, since 2010. There, he has been leading the efforts to understand the effects of radiation damage on the microstructure and mechanical properties of materials related to nuclear and space applications. His research focuses on the use of ion irradiation and micro-scale testing as a viable alternative method for neutron irradiation and conventional testing. He has authored more than 70 papers in international journals and edited three special issues of “JOM” and “Metals” journal on these topics.