Title:

Understanding irradiation-induced embrittlement and defects ordering in metals under reactor conditions

Speaker:

Dr. Cheng Sun

Affiliation:

Clemson University

When:

Monday, September 16, 2024 at 11:00:00 AM   Add to Calendar

Where:

MRDC Building, Room 4211

Host:

Dr. Ting Zhu
ting.zhu@me.gatech.edu

Abstract

Predicting the behavior of materials in nuclear environments presents a significant challenge. The irradiation-induced damage to microstructure and its impact on mechanical properties of materials are critical for the performance of nuclear core components. Stainless steels are considered promising candidates for structural components in advanced nuclear reactors. However, these materials can suffer substantial degradation from irradiation damage, which can lead to volumetric changes, hardening, embrittlement, etc. In this presentation, we will discuss the impact of neutron irradiation on 316 stainless steels, focusing on void formation and the resulting void swelling-induced embrittlement. Under neutron irradiation, materials often experience gas transmutation, which contributes to gas-driven swelling and gas release, ultimately limiting the lifetime of core internals. One striking phenomenon is irradiation-induced ordering of gas bubbles, which can cause the formation of gas bubble superlattices. This superlattice structure is efficient for gas storage and mitigating bubble swelling. This presentation will also cover the mechanisms involved in the ordering of gas bubble under irradiation. The understanding of material behavior discussed in this talk is crucial for developing damage-tolerant materials for fission and fusion reactors.

Biography

Dr. Cheng Sun is an associate professor in the Mechanical Engineering Department at Clemson University. He earned his PhD in 2013 from Texas A&M University. Before joining Clemson in 2023, Dr. Sun worked at Idaho National Laboratory as a senior scientist and led the Structural Materials Group. His research focuses on fundamental challenges in nuclear materials, particularly their behavior under extreme reactor conditions. He has published over 90 peer-reviewed articles in international journals and has organized symposia at major conferences such as TMS and MS&T. Dr. Sun's work has received several prestigious awards, including the 2023 INL Laboratory Director's Award for Exceptional Scientific Achievement, the 2022 Rising Star Award from the Journal of Nuclear Materials, and the 2019 INL Laboratory Director's Award for Early Career Exceptional Achievement.

Notes

Refreshments will be served.