CorroZoom “Assessing the loading rate dependence of hydrogen environment-assisted cracking behavior in a wide-range of engineering alloys.” 

Assessing the loading rate dependence of hydrogen environment-assisted cracking behavior in a wide-range of engineering alloys

 Jimmy Burns, University of Virginia

Abstract

Environment-assisted cracking is a prominent damage mode for a wide-range of engineering materials and operational environments. Most basically, initiation and sub-critical EAC requires a susceptible material, a sufficiently aggressive environment, and a mechanical load. This talk will provide a historic review of the methods used to characterize this damage mode for qualification of materials and life management of engineering systems. There will be a specific emphasis on modern fracture mechanic approaches and standards used to quantify the crack growth kinetics (da/dt) as a function of a stress intensity (K) and various environmental conditions. Of particular importance is that historic literature shows that the applied loading rate (dK/dt) will strongly impact the environment-assisted cracking (EAC) behavior. However, there is not a systematic quantification of dK/dt dependencies or a rigorous understanding of mechanistic underpinnings of this behavior. Recent work employed a slow-rising K testing framework to quantify the dK/dt dependence (ranging from 0.2 to 20 MPa√m/hr) of EAC in a wide-range of material (Monel K-500, Custom 465, AA5456, AA7075, Ti 6-4, Pyrowear 675, and 316L) and environment combinations that encompass multiple proposed damage mechanisms. Results confirm a strong influence of dK/dt on EAC for material/environment combinations with modest susceptibility. These results are rationalized in the context of stress- versus strain-controlled fracture and a H-modified Ritchie-Knott-Rice crack tip damage model. Furthermore, the implications of these results on recent testing standardization efforts for environment-assisted cracking are discussed.

Biography

James T. Burns joined academia in 2011 and is currently an Associate Professor in the Center for Electrochemical Science and Engineering within the Department of Materials Science and Engineering at the University of Virginia. He was appointed as the Heinz and Doris Wilsdorf Chaired Research Professor in 2021 and the Copenhaver Fellow of the School of Engineering and Applied Sciences in 2024. Professor Burns received a B.S degree from the United States Air Force Academy in Engineering Mechanics (Materials track) with a Mathematics minor in 2002. He completed his M.S. and Ph.D in Material Science and Engineering at the University of Virginia in 2006 and 2010, respectively. After his commission into the US Air Force he served as an Aircraft Battle Damage Engineer and Assistant Aircraft Structural Integrity Program (ASIP) manager for the C-130 from 2002-2004 and as a Research Engineer at the Air Force Research Laboratory – Materials and Manufacturing Directorate from 2006-2010. His current research focuses on the intersection of metallurgy, solid mechanics and electrochemistry. Specifically, his group investigates the interaction of localized stress/strain with environment conditions, with a particular emphasis on behavior at the crack tip and H-metal interactions. In general, experimental data from controlled environmental testing are coupled with high fidelity characterization techniques to gain mechanistic understanding of the damage process; such knowledge is used to inform theoretical and engineering level models. He has been distinguished via the 2019 Engineering Excellence Award from the NASA Engineering Safety Center, the 2021 HH Uhlig Award from NACE International, and is a member of the editorial board for the International Journal of Fatigue and Engineering Fracture Mechanics journals. In 2025 Professor Burns was awarded the Presidential Early Career Award for Scientists and Engineers (PECASE) Award.

Please register and attend if you are interested by clicking here https://osu.zoom.us/webinar/register/WN_aWcZO7hDTZCFkz7uL0yKuQ