Event
MSE Seminar: Dr. Timothy Weihs, JHU
Wednesday, November 11, 2026
3:30 p.m.
Room 2108 Chemical and Nuclear Engineering Building
Sherri Tatum
301-405-5240
statum12@umd.edu
Biodegradable Metallic Implants: Current Challenges and Initial Applications
Abstract: While metallic implants such as orthopedic screws, vascular stents, and litigation clips are commonly used in load-bearing scenarios, their permanent nature can lead to complications such as stress shielding, long-term inflammation, and second surgical interventions for device retrieval. Magnesium (Mg) and its alloys offer attractive alternatives as they degrade safely in the body and offer an impressive combination of physical properties and degradation products. Mg’s density and elastic modulus are close to those of cortical bone and the similar modulus helps to reduce stress shielding in orthopedic applications. As an essential element in the body, Mg’s degradation products are tolerated well in vivo and its ions participate in critical physiological processes such as osteogenesis. These benefits and years of development have led to multiple clinical translations. I will begin by contrasting common permanent implant metals, such as stainless steel and Ti-6-4, with biodegradable Mg alloys and highlight translations into the clinical setting. I will then highlight three studies of Mg alloys: the development of biodegradable scaffolds through 3D weaving, the use of ML to direct thermal and mechanical processing to achieve superior resistance to deformation and degradation, and the impact of microstructure on in vivo performance.
Bio: Timothy Weihs, a professor of materials science and engineering, focuses on the fabrication, characterization, and application of reactive, structural, and biodegradable materials. He is driven by an interest in developing an understanding of how novel processing and chemistries can deliver unique microstructures and properties for scientific studies and specific applications.
In the area of reactive materials, Weihs began by developing sputter deposited, reactive multilayer foils as model materials for studying phase transformations and as local heat sources for soldering and brazing components. In 2002, he took a three-year leave of absence from Johns Hopkins to commercialize the foils as co-founder and CEO of Reactive NanoTechnologies (RNT). After selling the company in 2009, Weihs expanded his studies of energetic materials into reactive metal powders and structural energetic materials for bio and chem agent defeat and now directs the Materials Science in Extreme Environments University Research Alliance (MSEE) that sponsors the research. His group fabricates powders by ball-milling, ultrasonic atomization, and sputter deposition in an attempt to identify chemistries and microstructures that enhance their ignition and combustion properties.
In structural materials, Weihs leveraged thermal and mechanical processing methods to refine the microstructure of FeCo alloys for jet engine applications and then the microstructure and chemistry of Mg alloys for armor applications. Currently his group is working with Professor Falk to identify the role that dislocations and vacancies playing in enhancing solute clustering and precipitate formation in Mg and Al alloys. He is also working within the Center on Artificial Intelligence for Materials in Extreme Environments (CAIMEE) to accelerate the development of novel metallic alloys, particularly by fabricating thick foils in a combinatorial manner for the automated Artificial Intelligence for Materials Design Laboratory (AIMD-Lab).
For biomaterials, Weihs and his students are working with multiple partners to develop magnesium alloys for biodegradable medical implants such as screws for bone fixation, stents for atherosclerosis, and porous scaffolds for bone defects. In all cases they seek to identify the links between processing, microstructure, mechanical properties, and corrosion rates so that the implants degrade safely in the body while providing sufficient structural support until heal occurs. Static and cyclic testing and machine learning are used to guide processing steps and identify ideal microstructures. Lastly, his group is using 3-D weaving and additive manufacturing to create novel architected materials with enhanced permeability and stiffness.
Weihs is a member of the Materials Research Society; The Minerals, Metals and Materials Society; and a fellow of the American Society for Metals. His awards include an NSF Career Award, a 3M Young Faculty Fellowship, an R&D 100 Award, an Innovator of the Year Award, the TMS Application to Practice Award, induction into the National Academy of Inventors, and a Fulbright Fellowship.
Weihs received a BA degree from Dartmouth College in 1983, then earned bachelor’s and master’s degrees in engineering from the Thayer School of Engineering in 1985. He received his PhD in materials science and engineering from Stanford University in 1990 before conducting postdoctoral research at Oxford University in England and at the Lawrence Livermore National Laboratory in California. He joined the Johns Hopkins faculty in 1995. Weihs directed the Center for Leadership Education at Johns Hopkins from 2010 to 2017 and currently directs MSEE.
