Swaminathan Ganesan
@psgitech.ac.in
Assistant Professor, Mechanical Engineering
PSG Institute of Technology and Applied Research
EDUCATION
Ph.D. in Metallurgical and Materials Engineering
M.E. in Manufacturing Engineering
B.E. in Automobile Engineering
RESEARCH, TEACHING, or OTHER INTERESTS
Mechanical Engineering, Materials Science, Automotive Engineering
Scopus Publications
Scholar Citations
Scholar h-index
Scopus Publications
G Swaminathan, V Sampath, and S Santosh
IOP Publishing
Abstract The effect of adding Co on the temperature cycling behaviour of ternary Ti50Ni(50−x)Cox (x = 1, 2, 3) alloys was experimentally studied in this work. The alloys were prepared using a vacuum induction furnace, followed by subjecting them to homogenization, hot-rolling and annealing processes. The alloys were subjected to thermal cycling experiments in a nitrogen atmosphere by differential scanning calorimetry under stress-free conditions between their transformation temperatures. The results indicate that adding Co to NiTi alloys decreases their transition temperatures, improves the thermal cycling stability apart from suppressing the R-phase formation on cooling during cycling. The changes are due to the addition of Co introducing solid solution strengthening and generation of dislocations during cyclic phase transformations, as confirmed by the hardness test results and TEM micrographs, respectively.
Sampath Vedamanickam, Poojalakshmi Vageeswaran, Bharathy Jacob, Swaminathan Ganesan, and Khadambari Bhaskaran
Elsevier BV
Swaminathan Ganesan and Sampath Vedamanickam
Springer Science and Business Media LLC
Swaminathan Ganesan and Sampath Vedamanickam
SAGE Publications
In this study, the influence of upper cycle temperature (maximum temperature in a cycle) and the magnitude of applied stress on the functional properties of an SMA during partial thermomechanical cycling has been studied. A near-equiatomic NiTi SMA was chosen and tested under different upper cycle temperatures (between martensite finish (Mf) and austenite finish (Af) temperatures) and stress level (below and above the yield strength of the martensite). The upper cycle temperature was varied by controlling the magnitude of the current supply. The results show that a raise in the upper cycle temperature causes the permanent strain to increase and also lowers the stability. However, decreasing the stress imposed to a value lower than the yield strength of the martensite improves cyclic stability. The upper cycle temperature was found to influence the crack nucleation, whereas the applied stress level the crack propagation during partial thermomechanical cycling of SMAs. Therefore, decreasing the upper cycle temperature as well as the magnitude of stress applied to lower than the yield stress of martensite have been found to be suitable strategies for increasing the lifespan of SMA-based actuators during partial thermomechanical cycling.
G. Swaminathan and V. Sampath
Springer Science and Business Media LLC
G. Swaminathan, V. Sampath, and S. H. Adarsh
Springer Science and Business Media LLC
G. Swaminathan and V. Sampath
Springer Science and Business Media LLC
Ganesan Swaminathan and Vedamanickam Sampath
Trans Tech Publications, Ltd.
Shape memory alloys (SMAs) find use in myriad medical and engineering applications. In these applications, the functional characteristics of the materials are capitalized on. SMAs are used repeatedly over a long period of time in service. With continued usage degradation occurs in their functional properties, leading to a change in recovery strain, recovery stress, phase transformation temperatures and hysteresis. The change in the functional characteristics of the alloys is known as functional fatigue. Functional fatigue affects the performance of the alloys with the alloys losing their intended functionality. This problem is to be addressed if the alloys are to be used effectively and efficiently throughout their lifespan. It is especially important when using the alloys within the human body, where such degradation can affect the performance of the biomedical devices and, in turn, human health and life. Till date not too many researchers have explored this area in greater detail. In order thereforeto better understand this behavior, in the present study, an Ni50Ti44.7Cu5.3 alloy wire with a d=1.43 mm and a l=100 mm was cycled (10,000) under constant stress (55 MPa) between its transformation temperatures, which were determined by DSC (without load). The effect of cycling on the shape memory properties (strain recovery, hysteresis, and transformation temperatures) after a specified number of cycles at regular intervals are considered. The results show that there is considerable difference in the properties obtained and are interpreted and discussed in detail in the paper.
N. Ajay Guru, G. Swaminathan, P.R. Prasanna Venkatesh, and P. Aravind
Elsevier BV