Dr. Dipankar Banerjee, Professor in the Department of Materials Engineering at Indian Institute of Science, Bangalore, India, will give a seminar titled "A Description of Dwell Fatigue in Titanium Alloys" to the interested faculty and students at Discovery Park.

Abstract

Over the past 30 years, titanium and titanium alloy production practices have matured more rapidly than perhaps any structural material in the history of metallurgy. These highly successful applications have been guided by enlightened empiricism covering the practical aspects of Ti ingot melting and processing into mill products, and secondary fabrication. With a temperature capability approaching 550C, titanium alloys were recognized as a suitable material for critical rotating components such as discs and blades in the low to high pressure sections of the compressor of gas turbine engines. However, significant gaps in physics-based models that capture the various phenomena that govern these engineering processes continue to exist even as models evolve. One such phenomenon is ambient temperature dwell fatigue in gas turbine applications, an unusual source of cyclic life debit because dwell life debits are usually associated with creep-fatigue interactions at temperatures where climb-controlled deformation mechanisms are operative. The specific phenomenon of ambient temperature dwell sensitivity was first recognized in late 1972/early 1973 through the uncontained failure of two titanium alloy fan discs in Rolls-Royce RB211 engines, and other engine failures in operation have occurred since then. The subsequent years have seen extensive effort to understand the origins of dwell fatigue life debit in titanium alloys. These studies have been informed by the development of vastly improved modeling of deformation behavior based on crystal plasticity techniques and EBSD-based characterization capability. The current understanding of this phenomenon is elaborated, and our recent work over the last few years to extend this domain of knowledge is described.

Biography

Prof. Banerjee graduated from the Indian Institute of Technology, Madras, in 1974 and obtained his PhD from the Indian Institute of Science in Bangalore in 1979. In his early research career, Dr developed an understanding of the structure-property relationships in titanium alloys and intermetallics based on the Ti2AlNb system for high temperature applications. As the director of the Defence Metallurgical Research Laboratory in India from 1996 to 2002, Dr. Banerjee provided leadership for many critical defence related materials programs. As Chief Controller of R&D of India’s Defence Research and Development Organization from 2002 to 2010, he coordinated military engine, combat aircraft, UAV and airborne surveillance programs. Since 2010, he has been on the faculty of the Department of Materials Engineering at the Indian Institute of Science, where he leads a group focusing on processing-structure-property relationships in engineering alloys with an emphasis on titanium alloys.