Woodruff School of Mechanical Engineering
Faculty Candidate Seminar
Materials and Manufacturing Innovations
Dr. Vamsi Krishna Balla
CSIR-Central Glass & Ceramic Research Institute, Kolkata, India
Monday, March 10, 2014 at 11:00:00 AM
MRDC Building, Room 4211
Dr. Suman Das
During the last few decades significant improvements in both surgical techniques and implants have led to great success in alleviating the pain and restoring lost functions of the joints such as the hip and the knee. However, most of the current orthopaedic implants often exhibit limited service life due to inadequate mechanical, tribological, biocompatibility and osseointegration properties, apart from issues related to design and surgical procedures. In this talk I will discuss how my research addresses these issues to improve in vivo stability of artificial implants without stimulating undesirable effects. The first part of the talk will provide a brief overview of my current research activities aimed at developing manufacturing routes for orthopaedic implants and biomedical devices at affordable cost. Notably, my recent research reveals that simple laser surface melting can mitigate toxic Ni ion release from the most economical implant material 316L stainless steel and hinged metacarpophalangeal joint prosthesis design can potentially improve the service life and reduce rejections of current silicone implants. The second part of the talk is focused on how additive manufacturing technologies can solve two key issues associated with current load-bearing orthopaedic implants. I will discuss our understanding of the formation and properties of TiB-TiN reinforced Ti alloy in situ composites and their potential in reducing wear-induced osteolysis associated with articulating surfaces of bone implants. To eliminate stress shielding of artificial load-bearing implants the effective modulus of medical alloys has been tailored by incorporating porosity to suit natural bone. X-ray micro-computed tomography assisted deformation analysis reveals the clear dependence of mechanical properties on pore distribution enabling more implant design options. These porous medical alloys are found to sustain cyclic compression fatigue stresses up to 1.4 times their yield strength without failure. Further, we discovered that the inherent brittleness associated with solid-state sintered porous materials can be completely eliminated via laser processing. Overall this research demonstrates that novel materials and structures for next generation orthopaedic implants can be easily realized using additive manufacturing technologies. To conclude, I will discuss my future research and collaborating plans in the areas of additive manufacturing of nanostructured materials and light weight cellular structures/coatings, novel high entropy alloys and in situ ceramic composites coatings, and non-invasive wound/bone healing devices.
Dr. Vamsi Krishna Balla is a Senior Principal Scientist and Head of the Bioceramics and Coating Division at Central Glass and Ceramic Research Institute, India. He received his Ph. D. (2005) in Metallurgical and Materials Engineering from Indian Institute of Technology Madras, India. Subsequently, he was a postdoctoral researcher (2005-2007) and Assistant Research Professor (2007-2011) in the School of Mechanical and Materials Engineering at the Washington State University. His research concentrates on the fundamentals and applications of additive manufacturing towards various long standing challenges in metal and ceramic implants. He carried out first generation research, including design, fabrication and testing, on developing novel implant structures using laser-based additive manufacturing technology. His current research includes orthopaedic implants design and development, engineered porous ceramics, functionally graded coatings, laser-assisted alloy development and biomaterials. Presently Balla’s research group is collaborating closely with orthopaedic surgeons and other research institutes to develop in-situ composite coatings, ceramic composites/scaffolds, nanopowders for drug delivery and biosensors. Balla has supervised more than 15 graduate and undergraduate students including 2 dental surgeon dissertations. He is a reviewer for more than 20 international scientific journals and funding agencies. He currently serves as an Editorial Board member for two international journals and as a Board Member of the Indian Orthopaedic Research Society (IORS). Dr. Balla publications include over 80 peer reviewed journal articles and 3 book chapters, which have been cited over 1100 times.
Refreshments will be served.