R. Vaidyanathan, University of Central Florida, Orlando, FL
NiTiFe shape memory alloys can undergo transformations between cubic, trigonal and monoclinic phases at low temperatures. The low hysteresis associated with the trigonal R phase transformation makes them candidates for actuator applications at low temperatures. This talk will present an overview of ongoing National Science Foundation (NSF) and National Aeronautics and Space Administration (NASA) funded research to develop NiTiFe alloys for low temperature thermal switches. Aspects addressed will include: thermomechanical processing of NiTiFe alloys; testing using in situ neutron diffraction during loading at cryogenic temperatures at Los Alamos National Laboratory (LANL), instrumented nanoindentation, liquid helium dilatometry and differential scanning calorimetry; incorporation of NiTiFe actuator elements in prototype thermal switches and their subsequent testing. The development of a new capability to investigate deformation in shape memory alloys at cryogenic temperatures on the Spectrometer for Materials Research at Temperature and Stress (SMARTS) at LANL will also be outlined and recent measurements on NiTiFe at 92 and 216 K will also be presented. Support of NASA (NAG3-2751), NSF (CAREER DMR-0239512) and SRI grants is gratefully acknowledged.
Summary: Information about author: Raj Vaidyanathan received his BS in Chemical Engineering (Summa Cum Laude) from Lafayette College (1994), MS in Materials Science and Engineering from Stanford University (1995) and PhD in Materials Engineering from MIT (1999). His doctoral thesis used neutron diffraction to investigate shape-memory alloys and was awarded the 17th Louis Rosen Award from Los Alamos National Laboratory. Following his doctoral thesis work, he was a Post-Doctoral Associate in Prof. Subra Suresh's Laboratory for Experimental and Computational Micromechanics (LEXCOM) at MIT. Starting in February 2001, he was an Assistant Professor at the Advanced Materials Processing and Analysis Center (AMPAC) and the Mechanical, Materials and Aerospace Engineering Department at the University of Central Florida (UCF), before being tenured and promoted to Associate Professor in August 2005. His research program at UCF is funded by the National Aeronautics and Space Administration (NASA), psiloQuest, Siemens Power Generation, Office of Naval Research and the National Science Foundation (NSF), including a Faculty Early Career Development CAREER Award from NSF.
