Su, Qing. Dual beam irradiation stability of amorphous silicon oxycarbide (SiOC)

Principal Investigator
First Name:
Last Name:
University of Nebraska-Lincoln
Research Assistant Professor
Team Members:
Name: Institution: Expertise: Status:
Michael Nastasi University of Nebraska-Lincoln Ion solid interaction, radiation defects in materials Faculty
Experiment Details:
Experiment Title:
Dual beam irradiation stability of amorphous silicon oxycarbide (SiOC)
Describe the work that you are proposing in detail. Please include as many specifics as possible (e.g., dose, dose rate, ion energy, types of ions, beam line x-ray energy, irradiation temperature, analysis temperature, atmosphere, etc.):
The amorphous SiOC films with film thickness of 1 micron will be prepared by magnetron sputtering process. These specimens will be subjected to dual beam irradiation (1 MeV Si irradiation plus 50 keV He implantation) at three different temperatures (room temperature, 300 and 500 °C). The irradiation damage will be up to 100 dpa and He peak concentration will reach 10 at.%. After the irradiation, proton backscattering spectrometry (p-BS) will be used to detect He concentration in SiOC systems after irradiation at different temperatures. Structural characterization and mechanical property evaluation will be carried out using and transmission electron microscopy and nanoindentation facilities at Center for Advanced Energy Studies (CAES) Microscopy and Characterization Suite, respectively. The micropillar compression test will be performed in the the Nano-Engineering Research Core Facility at University of Nebraska-Lincoln.
Technical Abstract
The objective of this project is to evaluate dual-beam irradiation stability of amorphous SiOC under extreme conditions of radiation damage. The limited resistance of current engineering materials to radiation damage is a key factor restricting the design of next generation nuclear reactors. Unlike the radiation responses of crystalline solids, which have been studied for decades, the fundamental processes by which amorphous alloy respond to irradiation have received relatively less attention and are therefore still largely unknown. Our preliminary results show that SiOC is resistant two individual types of irradiation damage: ion-induced displacement damage and degradation due to implanted helium (He). A prime hypothesis of this proposal is that the atomic displacing process and subsequent structural changes do not degrade the amorphous structure and He outgassing capability, radiation-induced damage and He impurity can anneal out and outgas as fast as it is created, allowing these alloys to persist indefinitely in an externally driven steady-state. To test the above hypotheses, we will carry out dual beam irradiation (1 MeV Si irradiation and simultaneous 50 keV He implantation experiment) on SiOC films with damage level to 100 dpa and implantation level to 10 atom %. The evolution of microstructure and mechanical properties will be investigated via transmission electron microscopy, proton backscattering spectrometry, nanoindentation and micropillar compression test. The potential results will be used in the development of a new class of ceramic material that can be adapted for engineering applications in advanced nuclear reactors with improved materials performance, and provide an important contribution to the state of knowledge in reactor materials science.