MMAE Seminar - Dr. Keivan Davami - Failure Prevention in Additively Manufactured Materials through Design and Postprocessing

Armour College of Engineering's Mechanical, Materials, and Aerospace Engineering Department will welcome Dr. Keivan Davami, Assistant Professor in the Department of Mechanical Engineering at Lamar University, on Tuesday, April 9th, to present his lecture, Failure Prevention in Additively Manufactured Materials through Design and Postprocessing.

Abstract

Additive manufacturing (AM) technologies are already revolutionizing a broad range of sectors, including aerospace, defense, automobile, and biomedical industries. AM technology benefits these industries in terms of reducing cost, weight, waste, fabrication complexity, and novel functionalities. This talk will consist of two parts: the first part will focus on additively manufactured self-healing structures, and the second part will concentrate on the laser shock peening of traditionally and additively manufactured superalloys.

Self-healing materials have the ability to partially or completely restore their mechanical properties by healing the damage inflicted on them. These materials have great potential for applications where there is no or only limited access available to conduct a repair. Here, we present a new type of additively-manufactured polymer-based self-healing structures with extraordinary mechanical performance, capable of autonomous self-repair under cyclic loading conditions. Throughout our mechanical analysis, we observed that a crack developed under 3-point bending tests was healed with minimum interventions. Repeated healing was achieved when the structure was subjected to multiple loading cycles (up to four). Not only do our self-healing materials outperform other previously reported self-healing materials like structures with microcapsules and microvascular systems with single- and dual-network in healing efficiency (52%), they also offer the remarkable advantage of facile preparation and short healing time.

For many AM parts, fielded components need to endure foreign object damage (FOD) and fatigue loadings over long operational lifetimes. Laser shock peening (LSP) is a potential solution to increase the durability of AM parts and decrease their sensitivity to foreign object damage. In the second section of the presentation, laser shock peening process and its effects on the nanomechanical properties of an aero-engine Ni-base superalloy, IN718, are discussed. The primary goal of this ongoing research in collaboration with Curtiss-Wright Surface Technologies is to obtain the required fundamental knowledge of the impact of LSP process parameters on the microstructure, residual stress and local properties of additively manufactured superalloys.

Biography

Dr. Keivan Davami is an Assistant Professor in the Department of Mechanical Engineering at Lamar University. Before joining Lamar, he was a research scientist in the Navy Research Lab in Washington D.C. as well as a postdoctoral research scholar at the University of Pennsylvania. He received his M.S. in Mechanical Engineering with a focus on Manufacturing from the University of Tehran and his Ph.D. in Nanotechnology from Pohang University of Science and Technology in South Korea under the supervision of Prof. Meyya Meyyappan of NASA. His work during his postdoctoral studies at the University of Pennsylvania on ultra-lightweight metamaterials published in Nature Communications has been recognized widely both nationally and internationally. Dr. Davami's research interests are focused on advanced manufacturing techniques, in particular, additive manufacturing. His research has been supported by federal agencies such as the National Science Foundation and the Department of Defense as well as state funding organizations. He won an NRC Research Associateship award from the National Academies of Sciences for his proposal on phase transformations of materials.