Radiation Effects: Challenges and Opportunities for Nanoscience and Engineering

McDonnell Douglas Engineering Auditorium

ChEMS Seminar

Professor Lumin Wang

Department of Nuclear Engineering and Radiological Sciences

Department of Materials Science and Engineering

The University of Michigan,

Ann Arbor, MI

 

The interaction of energetic particles with the atoms in the crystalline solid creates lattice defects. The exact fate of these defects or defect clusters in the nanoscale determines the performance of the material in a radiation environment. Typical radiation effects observed in metals and ceramics under the TEM include nanoscale void/bubble and dislocation loop formation, chemical segregation, irradiation induced precipitation and dissolution, with the “ultimate damage” considered to be solid state amorphization.  These changes at the nanoscale lead to macro-scale effects such as volume swelling, embitterment and accelerated stress corrosion cracking, increased corrosion and leaching rate, thus early failure of the material.

While nanoscience and engineering have been used to develop radiation tolerant materials, such as oxide dispersion strengthened alloys (ODS), radiation effects can also be utilized to generate various types of unique nanosctructures. The formation mechanisms for some of these structures are still not well understood. This talk will review the nanoscale radiation effects observed by the speaker’s research team, emphasizing examples that show radiation induced nanopatterning and how a group of amorphized material can be further damaged to form a nanoporous and fibrous assembly.

Bio:

Lumin Wang received his PhD in Materials Science from the University of Wisconsin-Madison in 1988.  He worked at Argonne National Laboratory as a post-doctoral fellow and University of New Mexico as a research scientist/manager of the TEM laboratory before joining the faculty at the University of Michigan (UM) in 1997.  Lumin’s research interest has been on nuclear engineering materials, nuclear waste management, nano-scale transmission electron microscopy (TEM) characterization of irradiated materials, including metals, ceramics and semiconductors.