MIME FACULTY CANDIDATE SEMINAR • WINTER 2013 Process-Property-Performance Paradigm in Hybrid Manufacturing of Biodegradable Metallic Materials By Dr. Meisam Salahshoor Georgia Institute of Technology Abstract Ever increasing challenges in providing quality medical implants have inspired researchers across the materials and manufacturing disciplines to push the boundaries and bring novel solutions into the realm of possibility. Properties of biomaterials determine their in-vivo performance. These properties, on the other hand, are heavily influenced by the governing mechanics during the manufacturing stage. The fundamental understanding of the science associated with process-property-performance relation where advanced biomaterials are paired with multiscale manufacturing processes is necessary to develop next generation of implants with superior bioperformance. In this seminar, the development of a novel biodegradable orthopedic material with adjustable degradation rate will be discussed. Annually, millions of bone fractures caused by accidents or bone-related diseases occur in the USA alone. This trend is expected to witness a rapid escalation in coming years due to increased life expectancy. When bone fractures, the fragments lose their alignment in the form of displacement or angulation. For the fractured bone to heal without any deformity, the bony fragments must be re-aligned to their normal anatomical position. Orthopedic surgeons attempt to recreate the normal anatomy of such complex bone fractures by placing implants over or within bones to hold the fragments. Orthopedic implants are traditionally made out of Ti alloys, Stainless Steel, or Cobalt-Chromium alloys and have one major drawback: their stiffness is significantly higher than the adjacent bone which leads to stress shielding and artificial osteoporosis. Therefore, second surgeries with all the personal, medical, social, and economic consequences have to be performed in order to excise these implants after the healing is over. Biodegradable implants with a more compatible stiffness to the bone seem to be an ideal solution to tackle “stress shielding” and “second surgeries”. The currently available biodegradable materials are mostly polymeric which suffer from lack of sufficient mechanical strength in load carrying applications and subsequent restoration of undesirable misaligned bone fragments. On the other hand, Magnesium-Calcium alloys have comparable stiffness to that of bone and clinically-proven biocompatibility and biodegradability. However, the Achilles heel of these alloys is their fast degradation in saline media as in human body. To solve this problem, a synergistic experimental-numerical investigation of the process-property-performance relation in hybrid dry cutting-hydrostatic burnishing of Mg-Ca0.8 alloy was conducted, the details of which will be discussed in this seminar. The results of this investigation suggest that it is feasible to tailor degradation kinetics of the Mg-Ca0.8 implants at the manufacturing stage so that the degradation rate matches healing rate of the bone and absorption rate of the corrosion products under various physiological conditions. Speaker’s Brief Biography Meisam Salahshoor is currently a postdoctoral research associate at the manufacturing research center of Georgia Institute of Technology. He received a Ph.D. degree in Mechanical Engineering from University of Alabama (UA) on May 2012. He started his studies on process-property-performance (3P) paradigm at UA to develop a novel biodegradable metallic biomaterial with adjustable degradation rate. At Georgia Tech, he continues his studies on 3P paradigm in two fronts: 1) Harnessing the multiscale manufacturing potential of photovoltaic materials, and 2) Physics-based predictive modeling of Ti6Al-4V alloy behavior under extreme deformation regimes present in machining. Before starting his PhD, he worked for industry in variety of job functions as research engineer, consultant, quality engineer, and manufacturing engineer and has hands-on experience in broad-range of manufacturing processes. He is the recipient of 2012 Excellence in Doctoral Research Award and 2009 Graduate Council Research and Creative Activity Fellowship from UA. He also received a BSc. degree in Materials Science and Engineering on August 2002 from Sharif University of Technology where he focused on metal forming and computational process modeling. He is a member of ASME, SME, and ASM professional societies and Pi Tau Sigma, and Phi Kappa Phi honor societies. Wednesday, February 20, 2013 11:00 AM – 12:00 PM, Covell 117 (MIME Library) School of Mechanical, Industrial, & Manufacturing Engineering