Date(s) - 04/02/2019
3:00 pm - 4:00 pm
Rhines Hall 125
Bai Cui, Ph.D.
Department of Materials and Mechanical Engineering
University of Nebraska-Lincoln
Laser shock processing (LSP) is a novel surface engineering technique, which utilizes a nanosecond pulse laser to generate plasma-driven shock waves that can induce high compressive residual stresses into a depth of more than 1 mm from the surface. Our research team has used experimental approaches to understand the processing-microstructure-property relationship of materials in LSP process, and revealed the fundamental mechanisms that enable LSP to improve mechanical and irradiation properties of metal and ceramic materials.
In austenitic steels, we found that the LSP-induced microstructures could improve the resistance to irradiation damage. The mechanism is related to the defect sinks generated by LSP such as dislocations and twin boundaries that can annihilate irradiation defects.
Compared to metals, LSP has not been widely applied to ceramics and its mechanisms on ceramics are less understood. We discovered that LSP of SiC and Al2O3 ceramics can induce localized plastic deformation near the surface and along grain boundaries at room temperature, resulting in high compressive residual stress. The compressive residual stress can improve the resistance to surface-originated crack growth, which may lead to new surface toughening mechanisms for ceramic materials.