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Vibration Characteristics and Damping Properties of Iron-Based Memory Alloy Produced by Melting

Eftekhary, Hosna | 2015

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 48185 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Sadrnezhad, Khatiboleslam
  7. Abstract:
  8. For measuring damping capacity of shape memory alloy, samples containing Fe- 27Mn-6Si-4Cr-4Ni were prepared. In order to produce the alloy 99% pure elemental powders were mixed and pressed in a matrix rod. The packed powders put in 15cc alumina crucibles were held in a 200 °C oven for 10 hours before they were melted inside two–layered alumina and graphite grucible an induction furnace. Resulting samples went under hot and cold rolling, thermomechanical treatment and were shaped into strips by wirecut. Chemical composition ascertainment, Tensile, bending, differential scanning calorimetry (DSC), micro hardness and modal tests were operated. Microstructural investigation was done using optical and electron microscopes. Test samples were glued to a contact vibrator and acceleration was recorded by a laser dupler vibrometer. The output data for every sample was presented as an acceleration-frequency diagram. Analysing the diagrams by STAR Modal software yielded one damping parameter for every sample. Results show that in certain circumstances the produced alloy has the damping capacity of 0.52% which is almost twice as much damping as a structural steel (0.3%) and 4 times greater than the resembling SMA with the damping factor of 0.11%. Grain size, chemical composition and micro –sized precipitates were the main reasons to the mentioned properties of the alloy
  9. Keywords:
  10. Ferrum Based Shape Memory Alloys ; Vibrational Damping ; Martensitic Transformation ; Shape Memory Effect ; Modal Test

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