The Department of Mechanical Engineering Presents

Process-Property-Performance Paradigm in Hybrid
Manufacturing of Biodegradable Metallic Materials
By Dr. Meisam Salahshoor
Georgia Institute of Technology
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